I've spent basically my entire life discussing things in the abstract. I'm not a politician, I don't make laws, and frankly I wouldn't want that power.
To me it makes absolute sense that someone would attempt to "defend" even the most heinous person. It's weird to me that being considered a "defender of X" could even be a bad thing. That's the process by which we collectively make decisions, it's the basis behind stuff like fair trials for example; the lawyer acting for a defendant is not a bad person. It's what (rational) individuals do when they make decisions - even some of the most obviously correct ones - take the opposing side and see where it leads.
It doesn't seem to be limited to this case - I don't know if it's a recent thing, having mostly come of age post-Internet. It's just like, really weird. Amongst my real-life friendship groups this sort of "hate mob" type stuff just doesn't exist, pretty much any topic is up for grabs.