Every significant cause has in some sense its own normal distribution of supporters and followers.
Hence, every significant cause has in some sense its own share of brilliant or imbecilic supporters and followers.
This does not directly impinge on the worthiness of said cause.
Conversation
"Yeah, but radical left students," is not a defense of ethnostates; "yeah, but antifa," has no bearing on neo-nazis.
It doesn't even matter if said bugbear is as bad as claimed or not: it just doesn't have any bearing on the worthiness of their enemies.
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Ultimately, what you label yourself as is as irrelevant as who your enemies are.
If you say you're a feminist, but advance causes detrimental to women, who cares about your self-labeling?
It's as laughable as people who lynch immigrants insisting they're, like, so not fascist.
Replying to
Culpability can travel down the chain. Calling yourself a neo-nazi is enough reason to shun you or worse.
It takes significantly more for it to travel the other way. The Nazis and Communists killed millions of people before these words became (almost) universal slurs.
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So, sorry, it takes a lot more than just a few delusional college students to ascertain a "rising threat from the radical left", politically speaking, but nationalist parties having double digit elections everywhere is a clear enough indicator of *that* threat.