There are other places to learn religion though - e.g. in a church. That's what places like that are there for. Children aren't using free will to choose their beliefs because most parents force on their children their beliefs - by the time they're old enough to decide what they want to believe, they've probably already been to church every sunday for the last 12 years of their lives. By then it's pretty much ingrained in them. That isn't exactly free will either so I don't see how churches are advocating for free choice.
A lot schools don't have philosophy classes - at least not public schools. So you'd still have the problem of where all the extra funding is going to come from to fund all these various optional religion classes.
The thing about learning a religion from a church or religious institution is that the learner might feel rather uncomfortable being that he or she is sitting within a place where everyone else believes in something different than he or she, and the teachings there would obviously be very subjective or biased. You might learn about Jesus' ministry but not of the history of the Crusades or the Inquisition. You might learn about Allah saving you if you follow him, but you might not learn about the condemnation of all those that don't believe in him to hell. There is no offense intended for any of those examples. Basically, you could learn about that religion in their respective religious houses, but you won't get the full story or get it in a format of objective teaching.
As for parents pushing their beliefs down their children's throats, that is exactly why I want other religious or philosophical teachings to be taught in schools. However, the fact that parents do that is not a religion's fault. Though some religions just tell their followers to force beliefs onto people, most religions really don't ask people to force those beliefs -- they just ask their current followers to preach and inform people of their beliefs. People are the ones that complicate that idea into forceful evangelization or any other form of preaching a belief. As for philosophy not being taught in schools, I also want all forms of philosophy, religion, etc. taught in schools quite simply.
If it is not for the value of philosophy in and of itself, then it is for its pertinence towards the history of all mankind. The past philosophies and religions are usually the main components in a justification of a historical action, the destruction of a whole nation, or the rise of a new nation such as the Holy Roman Empire. In that way, philosophy and religion are probably even more important than most of the teachings in history classes in this day and age. We should at least know what those philosophical or religious practices are by being taught it in an objective and factual manner.