Let me just be more explicit: if your software cannot be used by nazis then your software is not free software.
This is not the correct place to fight hate speech. Block the instances. Report hate speech to the authorities. Settle it using the existing legal frameworks to do so, and if they are insufficient, then write to your lawmakers.
But if you support free software, it is not the place to address this issue, by definition.
Gablins can go maintain their own goddamn fork of software that doesn't do what they want, just like the rest of us have to fork tootsuite because it's run by an obstinate twitter-licker.