I'm confused, do you seriously think the AfD runs on phrases like "we want to get rid of the democratic system"?

It's actually quite the opposite, they are running on things like a direct democracy[0], with phrases such as "Wir sind überzeugte Demokraten"[1] (eng: We are confident democrats). And they do that for good reason, as running a party that openly wants to abandon the democratic process would be against the constitution.

[0]: https://de.wikipedia.org/wiki/Alternative_f%C3%BCr_Deutschla...

[1]: https://www.afd.de/wp-content/uploads/2018/01/Programm_AfD_D...

No, because it may cause the violation of basic human rights of minorities.

However, it is in our democratic right to fight parties that are anti constitutional. It's in the constitution.

The rest of the world did object the last time we did that. I'd prefer if we don't try that again, and our constitution is specifically set up to prevent this.

No, article 20 of the German constitution forbids this, and article 79 forbids changing article 20 in the way you suggest.

Edit: There is a loophole, though. Article 146 allows the German people to replace the constitution in its entirety.