Here's one reason to think so.
Arminians seem to (I say "seem" because this whole business of "author" is terribly confusing, it's not even clear that they know what they're claiming; not only that, they use stipulative definitions of the term, and also change their definition of the term mid-debate, all of this is very confusing) claim that authoring some X means determining that X, originating that X, being the ultimate source of that X, and removing any responsibility an agent who did what was authored has, i.e., the act is not his own. Here's some quotes from arminian epologists:
The term ‘author‘ as employed by Arminians/Synergists in this case, is used in an originative sense to describe where the evil ultimately arose from. If we can identify, “whose idea was this?“, then we’ve found the author.
It always ends up being unconditionally due to God’s decree. Clearly, all the rhetoric about sin proceeding from man’s evil motives is simply an evasion of the real issue, since to the high Calvinist, even the evil motives themselves don’t come from man’s abuse of his independent will, but irresistibly arise from God’s decree
"So, by alleging that Calvinism makes God the "author of sin," I am insisting that Calvinism teaches that God "puts the initial conditions in place" for every event, so that whatsoever comes to pass does so because of God's foreordaination, decree, will and pleasure. Absolutely nothing comes to pass that was not at God's initiation. And due to this, God is the author of sin."
[When it comes to "author of sin"] "Grudem naturally assumes that people understand what he is trying to convey by using terms such as God "causing" everything that comes about in the world, or "causing" the evil actions that people do, or that God might be "responsible" for sin, etc."
"Still, it is insisted, God is not the author of sin. He is not responsible for bringing about all of the things which He brings about. He is not culpable for influencing the desires and decisions of people. God is not the author of sin. Why? Because Calvinists say so."
"How any reader cannot clearly understand how Calvinism makes God the author of sin is beyond good reason. In Calvinism, God is the Ultimate Cause behind every action, since every action was specifically suited and foreordained for each individual in just the way that God pleased by His decree."
I've also been told (by Bossmanham, for example), that if God authors an evil intention, it is his intention, he had an evil intention.
So it seems somewhat clear that if God authors your sin that means he determined it, controlled everything, ordained it, decreed it, originated it, was the cause behind it, was his idea or plan that the agent would do it, set the intitial conditions in place, etc.
But what happens to Arminianism when we look at, say:
1 Corinthians 14:33
For God is not the author of confusion but of peace, as in all the churches of the saints.
And having been perfected, He became the author of eternal salvation to all who obey Him,
looking unto Jesus, the author and finisher of our faith, who for the joy that was set before Him endured the cross, despising the shame, and has sat down at the right hand of the throne of God.
It would seem, then, that if Arminians are going to remain consistent, they need to become Calvinists! The faith they profess (that which God supposedly foresaw and then based his decision to elect on) is actually caused by God, originated in God, is God's faith, decreed by God, God planned that they would have it, God masterminded the whole thing (that they would have it), it was God's idea that they would have faith, God set up the initial conditions, etc.
We can do the same with peace and salvation. If "author" means what Arminians say it means, then they should become Calvinists. They should deny that God foresaw their faith apart from his decree, plan, origination. God masterminded their salvation, planned their salvation, caused their salvation, and set the initial conditions in place for their salvation to follow as a consequent.
If they are peaceful, they should deny that they are peaceful. They are not responsible for their peaceful disposition. If an Arminian is peaceful, he is a robot.
I suppose that the Arminian can claim that it is consistent with God's authoring their faith, peace, salvation, etc., that man has responsibility, that man originated the act in the morally relevant sense (e.g., it is really their faith, they are responsible for having faith, for "reaching out with a weak hand and accepting God's gift," etc). It is consistent that God didn't cause it, mastermind it, or have the faith in himself. That man can originate the foreseen faith in the relevant sense (to save their view of election). But if so, then they must admit the same for Calvinism. If authoring per se is consistent with this, then Arminians need another argument than the mere chanting of the mantra that Calvinism makes God the author of sin. But if they had that, they wouldn't need the author of sin argument. It would be superfluous.
I guess they can also say that authorship doesn't mean what they've been claiming, then they'd lose "the definition" of authorship and with it their argument against Calvinism. They'd need to go back to the drawing board.
Anyway, I guess I just don't get their argument, try as I might.