I went to college at a public university here in the states. When we got to the evolution chapters of Biology, multiple kids walked out in the middle of class sessions.
One day the professor came in and very sternly told us something along the lines of "If you disagree with this and you want to walk out, that's fine - remember, you're the ones paying to be here, and you're adults and that's your choice. But I'd like to re-emphasis the 'you're adults' part - it is unacceptable for me to be receiving angry letters from your parents. If you don't pass this class because you walk out, that's on you and you need to own that consequence." ~ oof, it was a rough Monday.
One day the professor came in and very sternly told us something along the lines of "If you disagree with this and you want to walk out, that's fine - remember, you're the ones paying to be here, and you're adults and that's your choice. But I'd like to re-emphasis the 'you're adults' part - it is unacceptable for me to be receiving angry letters from your parents. If you don't pass this class because you walk out, that's on you and you need to own that consequence." ~ oof, it was a rough Monday.