Eh, I actually think Germany banning Nazis was a good idea in hindsight, but there's some special context there. :P Specifically, looking at Germany, I don't think it's a Paradox of Tolerance situation because we've seen over decades of experience that the Nazi ban is not being broadened or overapplied. And there's no need for it, because the actual Nazis remarkably seem to be unable to help themselves, even given the very specific and limited ban we're running. So I'm going to explicitly carve out an exception for the Nazi ban in my otherwise liberal ideology - on consequentialist grounds, since as far as free speech restrictions go this one seems to be operating productively even within its sharply curtailed limits. In other words, it selects Nazis and approximately nobody else. If more limitations of free speech had the character of §86, I'd be a lot more on board with the concept.

In other words, the Nazi ban is one case where the dialog went like this:

"Come on, this is pointless, they can just use other symbols and dogwhistles. You'll fall into an escalating spiral of swatting down new Nazi symbols, negatively affecting pretty much everyone but Nazis."

"Yeah but look, we won't fall into an escalating spiral of free speech restrictions. Because they won't change their symbols, ever."

And they were right. I don't entirely understand why, but clearly they were right. My standing theory is that Nazis are either really dumb or in some sort of symbiotic relation with the constitutional protection office where going to jail is actually their goal. Works for me.

Tl;dr: my rule-consequentialist ethics don't have a problem with "liberalism, except where Nazi paraphernalia and holocaust denial", since those modifications have clearly demonstrated their worth and limited character.