This is pretty much the same as existing downvoting systems. People are supposed to use the down arrow as a distributed moderation, not to show disagreement, according to Reddit rules, yet they do it anyway. The same way, the troll button would also devolve into a disagree button.

I should also add, in an ideal world, there would be a way to make a difference between ideas expressed in a hateful tone vs. ideas that are branded hateful even if they are very gently and a friendly way put just because they do not mach "political correctness" norms. Hate can be an actual emotion (discovered by tone) or a judgement set by others.