I mean, it's the free speech argument and the slippery slope. Yes, they're garbage but they're entitled to their free discussion.There's also the fact that once they're banned, the cockroaches will just split up and flee to different "special snowflake" zones, making it harder to keep track of them.
It's a thorny problem that can't really be solved.
Do me a favor. Walk into your job and start calling your bosses and coworkers racial and gender slurs and act surprised when you get fired.