I agree that many AfD supporters aren't nazis. In fact, I'm a progressive but grew up in a fundamentalist Christian household in Germany and some of my best friends sympathize with the AfD because of their "Christian values".
However, you got to admit that the elected AfD politicians are often fringe-right-wing, talking of shooting refugees at the border, how they wouldn't want to have a black neighbor, an AfD local charter (Rottweil/Tuttlingen) even said they want refugees fleeing across the Mediterranian to "drown" to disincentivize other refugees to make the journey.
If you support the AfD for whatever reasons, then either you don't really know or think about those truly extremist things, or you support them, or you don't care either way. That has to be adressed, we can't pretend like THAT aspect of the AfD is "just another normal democratic party"
But other than that, sure we should talk normally to the SUPPORTERS of the AfD, we shouldn't demonize them, or rather only that fraction of them that sociopathically supports killing people. You can't convince people of your position or party by demonizing them, we learned that now and we learned it when Trump won while Hillary only put his supporters into a "basket of deplorables"
I'll answer in full when I'm free again. Thanks for contributing!