It's probably a five beer problem, Roger, which throws up more questions than answers. In the last local elections, the Fascist parties took around eleven per cent of the vote even in a liberal city like Cologne. Their sympathies were clearly Nazi, but there were certain restraints to what they could put on their posters. There will always be a condundrum of how to guarantee freedom of speech for everyone - including Fascists - but while imposing some restrictions on what sort of language can be used in public. I don't claim to know any better than you where that line should be drawn. I believe it has to be though.
Holocaust denial is a specific offence in German law - as is any overt incitement to racial hatred. This has placed a poweful weapon in the hands of the Berlin chief of police, for instance. He (bless him) has taken a very firm stance on the neo Nazis in his city.