My son had a similar school uniform when he was in So Cal private school…not a blazer, because he was younger, but a crewneck sweatshirt much of the time. He was allowed to take the sweatshirt off anytime he was outside running around, but otherwise, he had it on.

It’s not unreasonable…it’s actually not that far off of the dress codes of most offices in California. Actually, I think the dress code of the office I worked in was pretty similar, except we could wear whatever (conservative) colors we wanted to.

I’ve come across far stricter. You/ your folks chose the school, you have to abide by the rules. Simple as. If you can’t hack it, go to a normal school not a snob one.