I’m not saying this is acceptable. To me as a parent, it’s not. But I’m saying that you can’t legislate taste (or poor taste) out of their lives. You can NOT keep all distractions out of their sight and it’s far better to teach the children to ignore the sillier distractions. Of course when kids are warehoused in large groups, that is hard, but that’s what they do, it’s the school’s choice and responsibility.
Keep in mind that this is a charter school, which means that child had to meet a set of requirements to be admitted. If the school has a policy against weird hairstyles, so be it, that’s their prerogative.
But you’re right, no one can make a rule against any and all distractions to education...that’s impossible.