I am very curious too, I’ve asked this to other friends who have mentioned the same thing and the only concrete answer I have got so far was teaching the theory of evolution and climate change.

It's usually evolution or sex or race or something like that.

One of my friends was home schooled. It was at least partly about religious values, but I think it was also partly about him being a bit of a strange kid and getting along better at home. He went back to public schools in middle school, and that was real rough but I think he was happy by the time he got to high school.

I'm sure there are many reasons to home school, but the one I hear about most is religious.