You seem to be saying that people expounding on why they hold views different from your own are not engaging in discussion.
By the way, crying “slippery slope” is actually one of the classic rhetorical fallacies. As in, not a great thing to build your own argument on.
I’m confused, too, why free speech doesn’t extend to people protesting about the few available roles for people of color being given to a white actor. (Don’t even try Hamilton, which was covered adequately above.)