I assume they are referring to the word to mean 'courteous and polite'.

I personally believe you can hold abhorrent views and still be polite, so I don't see why there is a necessary contradiction here.

Yes. The discourse was courteous and polite, usually; folks would calmly discuss the most heinous horseshit and could actually in that setting be open to education about facts where available.

Its very hard to get people to learn things by shouting at them

It's hard to give a shit about educating people when they openly discuss wanting to murder you or eradicate people like you.

Yes. But at that point either you change their minds, or you gear up to kill them first.

It's weird how "change their mind or kill them before they kill you" is now widely considered a more just and equitable solution than simply not giving such people a platform to politely discuss your murder on to begin with. Much less the biggest possible platform.

I think there are other options that have worked pretty well in the past.

I would imagine they're civil to other Nazis but probably not so much to anyone else.