I don't see a reasonable way to avoid parents imposing their beliefs on their kids so this point you're trying to make is pretty weak man. You're comparing a problem with a very clear solution vs a problem with no clear solution. You wanna take the kids away from all religious people and all people with differing political views? Good luck with that.
Should all parents submit to frequent breathalyzers? Tell me, how many parents, as a fraction of all parents, drink irresponsibly to the point where it significantly endangers their children?
Now compare that number to the fraction of parents who drive their kids around in cars. You're grasping at straws comparing apples and oranges.