The usual problem I see is anti-"nazi" rhetoric quickly descends into dehumanization rhetoric about how such people don't deserve to live, should be ejected from all civil society, and must be relentlessly persecuted by every legal and social mechanism possible; in fact, all the suspension of every civil right is acceptable if it means stopping nazis. At the same time, it seems that almost everybody who lived in 1940 would be considered a Nazi by today's rather loose standards, and everybody tries to paint their opponents as nazis (even conservatives have the rather inept 'actually, Nazis were SOCIALISTS" retort) and apply this sort of rhetoric to what even 10 years ago was a completely mainstream liberal.
Certainly 4chan is full of reprobates of every flavor. But if you live in a society where the existence of Nazi rhetoric is actually dangerous, well, you've already lost your free society. People don't read deranged Internet rants and become mass murderers unless they were born in raised in an already broken, atomized society. The ideology is the excuse for the violence, not the cause. And unfortunately, this sort of rhetoric (we have to do whatever it takes to stop nazis) is also indicative of an worsening social environment.
And typically, in worsening social environments, where a variety of ideologies become excuses for broken and/or desperate people to become violent, the government will become more and more totalitarian in response. And we’ll cheer it along.
I know, I know for the sake of appearances we don't define everyone who disagrees with us as a nazi, that would be too obvious (although we still do alot).
We describe the broad spectrum of perfectly main-stream, otherwise unremarkable views (but that disagree with us) as "nazi supporters", dog-whistlers etc.
Too easy.