Well, I remembered that wrong. But I don't believe that banning the AfD will solve anything short, mid- or longterm. Times are quite different today than there were 70 years ago, so that's not a great comparison.
I really wish there was an easy and complete solution to getting rid of the AfD and their ideology once and for all, or at least to a degree, where these kinds of parties don't spring up again just a few years later to gain popularity once more.
The resulting radicalization of their voter base would cause quite a bit of damage, I am sure.