So rather than a long string of dubious arguments on the topic that overwhelms the opponent's ability to address them, you instead overwhelm them with mischaracterizations of the opponent's argument, which are more unbalancing due to their personal nature? And the icing on the cake is that if you call them out on it they can turn around and say "I'm just unpacking what you're saying, it's not my fault everything you say lacks clarity, rigor, and nuance, forcing me to step in and educate the audience on the topics you pretend to understand."
That's another part of it, if they can't call you a bigot outright, they suddenly demand that you have the academic rigor of a philosophy essay, with all terms defined, citations from approved sources &c. or it's just complete bunkum not even worth addressing.