I agree with you. Cult, sect, denomination, etc. are precise words for religious organizations of various sizes and degrees of formal organization. Some religious organizations in any category are unsavory, but some are not. Christianity itself began as a cult. The word cult is value-neutral. Even in England there are probably judges who are familiar-enough with the English language to see that the police have erred badly in this instance. The case will be dismissed.
Only English speakers are subject to penalty.
Exactly. I have had arguments with friends who think that “cult” means “occult”. Ignorance is what it is...