Pope Francis has instigated a crisis of authority in the Roman Catholic church. I'm guessing that from his vantage-point, he's attempting to do what Vatican II attempted to do. In this case, bring the Roman church into the 21C. He may feel that some venerable positions are unsustainable. They alienate too many people. For the Roman church to survive or thrive, it must adapt to modern challenges. It's losing too many members. Just look at how it's been decimated in the west.
The specific issues may be obscure to outsiders (e.g. evangelicals) because they hinges on assumptions that evangelicals don't generally share. Most evangelicals think there are two explicit grounds for divorce in the NT: infidelity and desertion.
Some evangelicals also contend that NT teaching on divorce is occasional. Not meant to cover every conceivable situation. So there may be additional legitimate grounds.
Moreover, most evangelicals believe that divorce and remarriage dissolve the previous marriage. Even if the new marriage was originally sinful, it's not continuously sinful.
Finally, most evangelicals believe that even if the new marriage was originally sinful, that's forgivable–like other sins. If, say, the couple were unbelievers at the time, but become believers, their sin is forgiven. What's past is past. Like having a child out of wedlock. That's sinful, but not continuously sinful.
My immediate point is not to defend evangelical positions, but to compare and contrast them to the traditional Catholic position. That has a different framework. As I understand it, this is why the new policy of Pope Francis is so controversial:
i) According to "irreformable" principles (Catholic dogma), marriage is indissoluble.
ii) To be divorced and remarried means living in mortal sin.
iii) 1415 Anyone who desires to receive Christ in Eucharistic communion must be in the state of grace. Anyone aware of having sinned mortally must not receive communion without having received absolution in the sacrament of penance.
iv) Hence, to intentionally open communion to recipients in a state of mortal sin facilitates evil.
So the controversy is generated by a clash between two "irreformable" principles: (i) the indissolubility of marriage and (ii) reception of communion in a state of grace.
This is a bomb inside the church of Rome. Unless defused, it will blow the church to smithereens.
The intentions of Francis are clear, but his words are unclear. His words are unclear because he wants to change "irreformable" principles, but he can't come out and say that directly without dynamiting the authority of the Magisterium. The best he can do is to send signals. That's his dilemma. That's why he refuses to clarify his remarks.
I'd add that this is not the only potential flashpoint. Francis also wants to liberalize church policy on homosexuals. He tipped his hand at the original synod. However, that's less rancorous at present because he communicated his intentions through intermediaries. He himself has yet to make that official policy.
At the moment he has his hands full with the current crisis. But if he prevails, he might revisit the issue of homosexuality in the church.
Francis has certain advantages. As pope, he holds most of the high cards. In addition, many professing Catholics are sympathetic to his initiatives. They consider that an overdue improvement. They don't care whether it contradics "irreformable" principles.