Religious persecution, or overbearing regulations?

Yes, it is. If it was about zoning laws and getting permits, fine. They should have just told them to get the permits or find a different venue for their activities. There is absolutely no reason for the police to ask those questions like that. Common sense left a long time ago.

I would also say the same thing for whatever type of meetings were going on there.
I will give you a reason, again. Neighbors complain of loud "praise the lords", "amens" etc being said in unison by a bunch of people. Cop does his job by investigating.