It’s all very well saying it doesn’t affect my teaching but then it doesn’t affect the kids learning either does it
and
The argument is usually that colorful hair distracts students from learning, but if a teacher having it doesn't distract them then I really doubt students having unnatural hair colours would be an issue in that way.
Colourful / extreme hairstyles distract students from learning because the are looking at each other and are a potential bullying flashpoint.
The students are meant to be paying attention to the teacher, so bright hair isn't an issue.
The other teachers aren't going to get picked on because their mum won't let them have / can't afford he latest haircut.
That's the logic anyway. Research shows it doesn't matter what the rules are as long as they are enforced consistently, but it seems that when asked, the majority of parents prefer a smart uniform and some rules around appearance and not taking £££ clothes to be lost at school.
(Teacher who couldn't care less what the students look like, but has to enforce the rules anyway)