After shutting off the angry notifications for a bit and having a private think, I retract my criticism of Tusky. So, some clarifications:
1. Obviously, I am against nazis. Fuck's sake, people can have complex opinions without being nazis
2. If Tusky had put an anti-nazi clause into their license, their software would be nonfree. Putting anti-nazi features into free software does not, however, make the software nonfree. Despite being usable by nazis I think free software is a good thing and nonfree software is a bad thing.
3. I would not have personally added such a change to my software, because I think it's immature and doesn't really solve the problem of nazis. In fact, it may exacerbate it. I maintain that there are much better ways to address these issues.
4. Anyway, Tusky is fine. It's dumb but it's fine.