Parents have the right to opt out but why Sex ed? Has it changed since I was in school? They only taught us basic reproductive health when I was a kid. Also put the boys and girls in different classrooms. Nothing unislamic.
LGBT stuff is part of it, it has changed over the years. Including safe s*, basically zina, teaching encouraging and facilitating it with contraceptives.
Why would a Muslim want a athiests/liberals from a state run school teaching their children about this?
There is no reason to send your kids to be educated by a secular liberal government school, but even if you do, it should be basics, math. reading, etc.
Parents should educate their own children on these kinds of things.