I think that we need to try letting them be in a set of rules that they think is fit, and just see if it is a good idea or not. You will never know if a program is going to work or not until you take it and see.
I use the analogy of the public square for this sort of thing. When you are in the public square, you adhere by the public laws and unspoken rules of civility. It doesn't matter if you're a shop open to the public, a public servant, or just an individual. You obey the laws we have all agreed on. When you go back to your homes, or your places of worship, you can add on your own religious rules however you want, among your fellow believers only.
This would be like me asking if baseball teams should be allowed to live according to their own rules vs. the laws of the country in which they live. We have seen when some of these cults--religions are cults--are allowed free-reign. Terror happens. Group suicide happens. It would be a disaster.
Religion is not a right everywhere. Even in countries that boast about religious tolerance still have certain criteria that is just not accepted as decent conduct. More often nations have rich historical ties to certain types of religion and those are welcome but the rest are not. The unfortunate part of allowing religions to conduct themselves as they deem fit is that a religion can claim to think sex with children is OK. That is the kind of thing keeping religion from being truly free.
No, I do not think that religious sects should be able to live according to their own laws instead of the laws of society, because people should be protected by the laws of the country in which they live. Anyone could just claim that their religion makes them believe differently. Young girls would continuously be abused.