Places of religious worship and formal teaching (e.g. churches, and Sunday schools) should be treated like bars and porn. You need to be an adult to access bars and porn because children do not fully understand what is happening or the consequences of being there. Churches (etc) are the same and there should be a legal age limit.
It should also be socially unacceptable to talk about religious opinions in front of kids, just like most people don’t swear or talk dirty, etc.
I agree with schools teaching kids “about” religions, just like sex and drugs. Teaching facts is good, preaching (aka indoctrination) is not.