Edit: made a stupid mistake in the first sentence, which I just corrected.
When I started reading your post, I thought you were being ironic and satirical, but when I got to the end, I realized you were being up-front. Wow.
The "rules are rules" argument is not a defense for the school administration. This is as stupid as "zero-tolerance" policies.
The only thing this student is guilty of is not checking with school administration before getting his head shaved. But it looks like such a stupidly rigid administration would not have granted an exception to the rules, anyway.
The reason rules and laws get so complex and unwieldly over time (requiring lawyers and judges to get involved, when complexity reaches a certain point) is that no rule or law can ever be written which addresses every possible situation and contingency. And that's why zero-tolerance and rigidity is ultimately stupid.
Here, we have a clear case of a student doing a lot of good, while breaking a rule. And his breaking the rule has virtually no negative consequences, other than the visible example of breaking that rule. This is a clear-cut (pun intended) example of a case where an exception should have been granted.
Rules and laws are not set in stone for all eternity. They are meant to adapt with the times, with society. But for this to happen, you need people to challenge those rules, otherwise, all you get is stagnation.