Send your kid to a religious school if that's what you want. But based upon what this country was founded upon, it's absolutely wrong and unAmerican to teach religion in a public school.
Separation of Church and State is a good thing, but I am not saying teach religion. I am saying teach that there are MANY religions..just as there are many hero's in history, many countries, many stars, much in science, how to add and subtract and multiply, etc etc etc.
The teaching of religion should be kept separate, yes. But at least let kids know there is a CHOICE and the origination of each belief.
Plus...this country was founded on Christianity. Wasn't it? Were not our forefathers who wrote the constitution relying on Christian beliefs when they wrote it? Does not our dollar bills have "In God We Trust" on them? The USA is steeped in Christian beliefs.