Couple was able to use kids for slave labor under the excuse that they were running a "school." If they'd have had to meet the same standards as a non-religious school they'd have never been able to get away with this shit. But because many states have exemptions for religious schools, they were able to simply pack up and move to another state after getting busted in the one they were currently operating out of.
I agree that there is a huge problem with government having to go through increased legal hoops to investigate and enforce laws on religious groups. I agree government should allow them to have freedom of beliefs, and that be protected to some extent, but that should not be an ability to violate laws based on social contract and evolving human morality. I also feel that taxation needs to start on the profit of running a religion. They use public resources therefor they need to pay taxes for their use.
There are many reasons religious exemptions are a bad idea. Whilst valid this isn't even in the top five.
I don’t think there is a single religious exemption that doesn’t lead to horrific abuse. Maybe the one for the Draft, but that hasn’t been a thing since Vietnam and I’m not sure if that really worked.