hnbad parent
Membership in an anti-constitutional organization is a crime under German law btw and I'm pretty sure there are other countries with similar laws. The US does criminalize membership but only as an add-on to other charges (co-conspiracy, basically). Of course in the US this is mostly for going after "gangs" so it's almost exclusively used against Black people.
Regarding Germany, that’s inaccurate. It’s a crime only if you wilfully (not just out of negligence) provide support for an organization after it has been prohibited. Membership is neither necessary nor sufficient for that. It’s what you actually do for the organization once it’s prohibited that counts.