This question seemed so idiotic to me. I mean, to counter it: "Should the government actively prevent parents from teaching their kids exclusively about one religion?"
Because that's basically what you intend when you propose the idea that parents forcing their religion on their children is wrong. Look, these are their kids. You might not like Christian fundamentalists or the like, but no one can honestly tell me that raising a child to be of a certain religion is a form of child abuse, which is what it would have to be to deny parents this "right." I mean, should parents who fail to give their children any religious guidance be held accountable in opposition? Fuck no on that, too.
See, here's the thing about children: they grow up. They gain independence, and they make their own decision. Yes, they are more likely to stick with the system of beliefs they were taught as a child, but that shouldn't mean that it's okay for anyone to tell parents that they cannot impart their religion (or moral code) on their own children.
Secondly, what are the conditions of forced? These are kids, for pete's sake. They're known to be irrational little snots. That's why there's a juvenile offender system. That's why they have limited rights. Unlike the government, or public schools, or churches, even, the parent-child relationship is not an institution. It is therefore allowed to discriminate. I'm not saying that it's right, but that giving up one thing like this allows for future interference. Maybe we should mandate what political leanings parents can teach their children, too.
Yes, getting religion "forced" on you sucks. But when you're a little kid, that's okay. You have questions. You're able to make the leaps of faith that faith requires more easily. You don't need to fight it, because you've got your whole life ahead of you in which to fight it.