I don't see how the other issues you list apply. schools don't advocate drug use or overeating.
even in NYC, the most liberal public schools around, gay textbooks were beaten back a few years ago. once gay marriage is legal, there will be no basis for stopping it anywhere.
No they don't. On the contrary they advocate against such things and expend tax dollars to say it's bad. They are teaching something that is probably best left to parents. Nonetheless it is "in the public" schools.