@izzythepush,
I am strongly opposed to the
US War on Terror. It is a disaster for civil rights.
The only thing close to the "proscribed organizations" you are describing in the US are "Foreign Terrorist Organizations" (FTOs). This are mostly Muslim (Edited: I just checked and several non-muslim groups from ETA to a Japanese violent cult are on the list).
I don't believe that mere membership in an FTO will get you arrested (I am not completely sure about that, but I hope you can't). My impression is that if they want to arrest someone for being part of a Muslim group, they trump up a charge of "material support". These laws are intentionally vague as a way to cheat civil rights. I feel strongly that this is a bad thing.
I am against making it illegal to be a part of any organization. If someone is in jail solely because of their membership or association with any organization, then absolutely they should be set free.
Unlike in the UK, In America organizations are not banned simply because they have the wrong ideology.