I am not a fan of excluding servers from the network because of their users. A better way is to confront the users, try to change their minds with arguments and, if there is no other way, make the network so unwelcoming to them that they leave of their own accord.
There are nearly 7,000 registered users on the nazi instance. Nearly every bad interaction I've had on the Fediverse has been with someone from the nazi instance (along with some sh.itjust.works folks saying the nazi instance is fine). I'd rather just wash out all 7000 users now. Granted, I'm not on discuss.tchncs.de, so my opinion has no weight, I just think it's something to consider