If it were just a question of someone putting together an exhibition full of frogtwitter memes than it would be hard to care either way. Idiot artworld edgelords thinking "ironic" racism and sexism are good ways to tweak the noses of the establishment is not a new thing, and neither is frantic overreaction from idiot artworld pharisees who can't tell when they're being baited. The two feed off each other, in a nova criminal spiral-of-escalation sort of way. The outcome is always a shitnado of boring ugliness and stupidity; anyone in their right mind would steer well clear.
The inclusion of Skype talks held in secret with straightforwardly fascist characters like Brimelow raises the level of aggro somewhat, to the point where I think it renders the free speech defense moot, unless you want to be fully absolutist about the issue, in which case I think you are going to look a bit ridiculous suing people for making shit up about you. An adequate response to "you are a fascist who wrote a text titled 'Towards a Hitlerian Disability Politics'" from most people would be to say "obviously I'm not, and obviously I didn't". Joe's problem is that he writes poems calling antifascists scumbags, and lectures denouncing the "psychological structure of antifascism" as projection and mental enfeeblement, alongside paeans to Trump's kingly charisma - which along with the Evola cosplay makes him look rather like the sort of person to whom writing something with that sort of title might occur as, at least, an amusing jape at the expense of those humourless lefties who think it's unkind and inappropriate to joke about such things.