Separation just isn't realistic when money is involved. The religious community has had far too much influence in politics for far too long in my not so humble opinion. If it were up to me they'd be paying taxes to express that opinion.
On the educational front, especially at the post secondary level, there is a left leaning political bias which has them pushing the positives of Islam while pointing out the many negatives of the other organized religions, especially those of the west. I don't really care what crazy shit they teach at that level of the educational system unless my tax dollars are used to teach it. Then it becomes my business. Don't want my input,then get your hand out of my wallet and they can teach whatever nutty belief system they want. I'm much more concerned with what they're teaching to, aka indoctrinating, young children, very young children. We're grooming an entire generation of mental and sexual misfits.
The conservative christians want to teach creationism in science classes.

