Like this is not just me mischaracterizing my political opponents, it is the most accurate label based on their behavior. They're the type of people who want to make the 1930s happen again in Germany.
This is why I react somewhat strongly when people try to relativize their abhorrence and make excuses, most frequently out of incorrectly mapping their own country's political systems.
I hope I could convince you that - especially given Germany's past and its commitment to never let this happen again - banning them is not some sort of political repression, but an immune response from democracy under attack. It is a manifestation of defensive democracy [0] , the principle written into the German constitution after the horrors of fascism.
[0] https://en.wikipedia.org/wiki/Defensive_democracy#Germany
If you seek to convince people then leading with the sort of examples you linked me is probably the way to go. For those open to new information it cuts to the chase and the rest you weren't going to convince regardless.
The trouble with the german approach that bans political parties is IMO that it creates an easily abused tool that muddies the water. It's no longer so simple to judge a given situation since now you need to consider the content and context of the speech as opposed to merely whether or not it constituted a direct threat of violence.
Meanwhile I don't think it's likely to be effective for the stated purpose. In one scenario the extremists get laughed out of the room as a tiny minority. In another they hold the majority in which case banning them is extremely unlikely to work out favorably. Imagine if Trump who won the popular vote this last time around had been banned by the sitting establishment. There's no way we come out of that unscathed.
Problem is, the German Verfassungsschutz (lit. "Federal Office for the Protection of the Constitution", the domestic intelligence agency) was itself infiltrated by the far-right [0] and so didn't ring the alarm in time.
I agree with you that there's probably no way to come out unscathed from trying to ban them now - their followers are already radicalized and it probably wouldn't be pretty. But that being said, what else should we do? Just do nothing and let it all happen once more? Break our promise of never again? Watch history repeat itself? No - we have to at least try.