I was raised Southern Baptist. When I stopped going, the church contacted me a couple of times to say they missed us and asked if everything was OK, and to say they'd love to have us back if we wanted to come back sometime. My parents weren't thrilled but that's less religion, more family dynamics: it was much the same when they found out I didn't support their preferred political party anymore. That was about it, though. The church didn't lean on us in any way, or tell people to stop talking to us, or use any other means to cajole or punish us.

My thinking on cults is very similar to all this, plus another distinguisher. A cult typically requires you to join before you get all the information about what you're signing up for. I've never been a Muslim, but know that if you walk into a mosque, someone will cheerfully greet you and load you up with a Koran and all kinds of other reading material. Same with any mainstream Protestant church, or the Catholic church, or Hindu, or Buddhist, etc. In fact, many/most churches won't let you join until you've shown that you understand that church's beliefs. Compare and contrast with, say, Scientology, which is notoriously different.