The instance seems to be mostly right wing trolls. I know defederating is unpopular but I don't think much is to be lost in this case and it can save the mods some headaches.
Edit: the response on exploding-heads.com to my reporting of transphobia. Courtesy of the "second in command"
The scale of it is a modern issue, far right extremists existed in the past, never have their ideas been as mainstream as they are today, social media and a certain politician gave them a reach they never had in the past. It's much harder to get people hooked when you have to meet them in person to recruit, now you just "question things" on digital public spaces and you'll have people who will start following you.
Isolating them is the solution because, for every one of them that gets out because they're exposed to other points of views, you've got hundreds or thousands being exposed to their message.
Moderation isn't instantaneous either so saying "We'll delete their message as they post it" just isn't a logical solution when you've got the capacity to just prevent them from taking part in the discussion in the first place.
They already have their spaces to radicalize themselves, the goal of taking part in discussions on general forums is just to get people to enter the spiral and to move the window of what is and isn't acceptable. Just look at what happened on /r/Canada, that place was becoming a right wing cesspool before metacanada was forcefully shutdown. Why? Because the mods decided to tolerate bigots.
https://youtube.com/playlist?list=PLJA_jUddXvY7v0VkYRbANnTnzkA_HMFtQ