I'll give you another example. Take the Hells Angels, or The Pagans MC clubs.

Those fellas even walk around with the "colors" daily. They blatantly wear their jackets and "rockers" showing their membership in those clubs.

You don't see them being rounded up for that do you? The answer is of course no!!

Because it is NOT a crime to belong to the club. even though prosecutors have designated those clubs as potential "criminal organizations"

If they cannot catch members selling guns, or dealing drugs. They are NOT charged. Why is that?

Because prosecutors need "criminal acts" - overt criminal acts, in order to form an indictment. Membership alone DOES NOT meet that criteria.