The concept of teaching comparative religion sounds great, but in practice I fear it is so deeply flawed that it should be dropped.
Should government-sponsored schools get into the business of examining religion? We know that they will not dare teach anything critical about islam. The islamist pressure groups will be all over them with accusations of islamaphobia, etc. So the kids will get the sort of dumbed-down make-believe view of islam that many of our leaders exhibit.
I would rather they teach nothing than teach lies.
With Christianity, we have the opposite problem. Kids will be taught that the Obama version of the Crusades, ie a brutal attempt at subjugating peace-loving muslims. How muslims came to take control of Christian and Jewish Holy Lands will be glossed over, as will the persecution that prompted the Crusades.
So again, PC lies will be presented as history.
In a perfect world, the Supreme Court would have stayed out of religion in schools disputes, and kids could be instructed in the faiths that created this country. Since that is not going to happen, it is better the schools just stay out of it altogether. They have enough problems without fomenting religious disputes.