I believe that US law enforcement takes the view that as long as the cults are not breaking the law, (ie: assault, murder) then legally they cannot interfere with their operations. Cults know this and use it to their advantage; however, they do engage in criminal harassment, which is illegal, though difficult to prove. If they do engage in harassment, this Cease and Desist Letter can be helpful, since it names specific criminal laws that the cults are breaking:
[
www.crcnyc.net]