Sending missionaries

1. The martyrdom of Christian missionary John Chau provoked critics of Chau from both ends of the political/theological spectrum. On the one hand you have the secular progressives. One allegation is that he represents white-American colonialism. Some basic problems with that allegation:
i) Was he Aryan? He seems to have a Chinese surname and appears to be biracial. I'm guessing he's Amerasian (or adopted). So he's a poor candidate for white colonialism.
ii) In addition, in what sense did he represent the forces of colonialism? Here's a definition:

colonies for settlement and colonies for economic exploitation
https://plato.stanford.edu/entries/colonialism/#Def

He doesn't represent either one. Is the USA planning to invade the North Sentinel Island?
iii) The Christian faith originates in the Middle East, not Europe. It's not a white man's religion, and it was around many centuries before the USA came into being.
iv) Then you have progressives who say Chau was violating the national sovereignty of the islanders. But aren't these apt to be the same people who support open borders with respect to immigrants and "refugees" to the USA?
v) Another objection raised both by secular progressives as well as some professing Christians is the risk of infecting the islanders. Yet that would preclude Christian mission to many people-groups throughout church history, before the advent of vaccines, antibiotics, and antivirals.
In addition, can the islanders count on everyone to respect their sovereignty? China is becoming increasingly aggressive and expansive. If their geographical isolation and lack of resistance makes the islanders fatally vulnerable to epidemics, then they need to develop some resistance, since they can't expect to live in a bubble forever.
What about medical missionaries?
vi) The bottom-line is that secular progressives despise the Christian faith. Ironically, the people who hate Christianity reveal their desperate need for the very thing they hate.
vii) If atheism is true, human life is worthless. It's impossible to wrong anyone. It's all about power and ruthless self-interest.
2. Chau also came in for criticism from Christians. Reformed author and pastor Mark Jones said he was "unimpressed" by Chau and compared him to Calvin's statement that "zeal without doctrine is like a sword in the hands of a lunatic."
i) Some Christian critics seemed to imply that if a missionary is murdered, that in itself is proof that he was a zealous fool. When I asked Pastor Jones if that applies to St. Stephen (Acts 9), he replied:

You're comparing John Chau to Stephen? Wow. At least Stephen's audience heard the gospel in their language. That's one major difference.

That's an interesting response. How, exactly, is a missionary supposed to master the language of a xenophobic, geographically isolated people-group? Are there grammars and lexicons of Sentinelese language? Are there recordings that provide the pronunciation? From what I've read, it's a language isolate. Presumably, the only way a missionary could learn their language is through immersion, which requires direct contact.
In Acts 14:8-13, Paul and Barnabas don't know the native language, which results in some confusion. Were they wrong to evangelize such areas?
3. Do Christian critics think evangelism is supposed to be risk-free? I asked them what Chau should have done differently to avoid getting killed. No answer. Should we play it safe. Write off countries where evangelism is hazardous?
4. Another objection is that Chau's action was illegal. But even if that's the case, Scripture says the duty of evangelism overrides any laws to the contrary (Acts 5:29).
5. Yet another objection is that he wasn't sent. He was a lone ranger. That raises a number of issues:
i) From what I've read, he was trained and sponsored by a missionary organization:
https://allnations.us/wp-content/uploads/2018/11/All-Nations-Nov-21-2018-News-Release.pdf
So Chau doesn't seem to fit the profile of a missionary Rambo. But suppose instead of going by himself, a mission team went to the island. If they all got massacred, would that satisfy the critics?
ii) Perhaps some critics would say his sponsor doesn't count because that's a parachurch ministry. Some Christians frown on parachurch ministry. They think missionaries must be sponsored by a local church. And in the Book of Acts we see some coordination between local churches and missionary outreach.
a) However, that's descriptive, not prescriptive.
b) Moreover, although Peter, Paul, and John are said to be "sent" by local churches, they had an independent mandate to evangelize. A direct commission from Christ. They didn't require permission or authorization from a local church.
c) Furthermore, we have passages like Acts 8:5 which says "Philip went down to the city of Samaria and proclaimed to them the Christ." There's no indication that he was sent by a local church.
d) What about denominational mission boards? What about missionaries who were sent, not by a local church but by the denomination–via the missions board? Does that count? A denominational missions board transcends the local churches that comprise the denomination. That can't be prooftext from Acts.
Then you have transdenominatinal mission boards. Does that count?
In the nature of the case, missionary outreach has an international dimension. That can't all be coordinated at the level of the local church. There need to be some overarching structures or "connectional" ministries.
iii) In addition, while Acts sometimes refers to people who are "sent", the sender isn't necessarily or even normally a local church. It can take the form of revelatory dreams and visions, Christophanies, angelophanies, Christian prophets, or an audible voice of God:

26 Now an angel of the Lord said to Philip, “Rise and go toward the south to the road that goes down from Jerusalem to Gaza.” This is a desert place. 27 And he rose and went. And there was an Ethiopian, a eunuch, a court official of Candace, queen of the Ethiopians, who was in charge of all her treasure. He had come to Jerusalem to worship 28 and was returning, seated in his chariot, and he was reading the prophet Isaiah. 29 And the Spirit said to Philip, “Go over and join this chariot” (Acts 8:26-29).
19 And while Peter was pondering the vision, the Spirit said to him, “Behold, three men are looking for you. 20 Rise and go down and accompany them without hesitation, for I have sent them.” 21 And Peter went down to the men and said, “I am the one you are looking for. What is the reason for your coming?” (Acts 10:19-21).
Now there were in the church at Antioch prophets and teachers, Barnabas, Simeon who was called Niger, Lucius of Cyrene, Manaen a lifelong friend of Herod the tetrarch, and Saul. 2 While they were worshiping the Lord and fasting, the Holy Spirit said, “Set apart for me Barnabas and Saul for the work to which I have called them.” 3 Then after fasting and praying they laid their hands on them and sent them off. 4 So, being sent out by the Holy Spirit, they went down to Seleucia, and from there they sailed to Cyprus (Acts 13:1-4).
6 And they went through the region of Phrygia and Galatia, having been forbidden by the Holy Spirit to speak the word in Asia. 7 And when they had come up to Mysia, they attempted to go into Bithynia, but the Spirit of Jesus did not allow them. 8 So, passing by Mysia, they went down to Troas. 9 And a vision appeared to Paul in the night: a man of Macedonia was standing there, urging him and saying, “Come over to Macedonia and help us.” 10 And when Paul had seen the vision, immediately we sought to go on into Macedonia, concluding that God had called us to preach the gospel to them (Acts 16:6-10).

Yet I'm pretty sure the critics of Chau are cessationists, so they don't think a missionary must be sent in that supernatural sense. But in that event they can't prooftext their position from Acts.
There is a famous passage in Romans:

14 How then will they call on him in whom they have not believed? And how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching? 15 And how are they to preach unless they are sent? As it is written, “How beautiful are the feet of those who preach the good news!” (Rom 10:14-15).

But in context, I believe that's alluding to Jesus commissioning the apostles. If so, a cessationist can't appeal to that passage. You also have Paul dispatching his deputies. But unless we subscribe to apostolic succession, that's unrepeatable.
6. Perhaps Chau went alone because he couldn't persuade anyone else to accompany him. They were too afraid. Or perhaps he didn't wish to endanger anyone besides himself. As a "person of color", he might have more entree with other "people of color" than a white missionary. He died trying, but his death is a Christian witness. Indeed, that's the etymology of martyrdom. It became a technical term for Christians whose willingness to die for their faith is a witness in its own right.