It's not a religion, it's a political ideology bent on the violent overthrow of the U.S. government (or any other)...and I think you call that treason which is punishable by hanging.
Rope sells should be brisk in the near future.
Islam was founded by Mohammad to use as an excuse to rile up the populace and get troops to enlist to go to war. This King, prophet , was a smart warrior, back then the people lived their lives by dictates of their faith, when promisses of wealth and land failed to get the subjects moving then a promiss of eternity of sex and wealth after death worked to get the males into his service.
All his teachings are directed to the earthly pleasures of men that they would have for eternity if they died for Allah. He formed an exclusive club that was a Mans club, no woman allowed.
Most faiths have a Prophet who God speaks to, this King was not stupid, he was well versed in the Jewish and Christian faiths. He at some time decided to become a Prophet also, Allah spoke only to him.
Unlike other Prophet he used females as beasts of burdens and appealed to the baser instincts of men at the time.
Over time this belief spread and now IS A valid faith, this is no Cult but like Scientology an excepted belief.
One can believe in the Spaghetti Monster as God but it has no Prophet. YET.