Whether we should have uniforms or not is a different question. Quite what any uniform should involve and how prescriptive it should be, is another question.
However, given we do have them, they need enforcing. If they aren’t enforced, then very quickly significant slippage happens - it’s a disobedience. Disobedience in uniform being tolerated, results in students thinking they can be disobedient about other things; homework, time keeping etc. Keeping control of the seemingly small things, creates an environment of expectation that other rules are followed and creates a productive environment. So, if you are going to have a policy it needs enforcing.
Schools often have very rigid policies with specific skirts being required and specific lengths, because any ambiguity results in lots of time wasted in arguments and debates and uncertainty. Clarity has huge benefits.
Lots of people ask on other threads about why there is bad behaviour in schools, or why their children don’t make better progress. Atmospheres where learning can happen and there’s a positive atmosphere dont just happen….they need a lot of hard work. Particularly in schools which have had a more troubled past or still have potential troubles, clarity of rules and clear enforcement creates an environment where learning can happen and the regular minor and frequent distractions can’t get a foothold and ruin the education for all.
So, I’d say if your school has a a clear uniform policy and it’s enforced, and other rules are enforced too, be glad. The impact is likely to be helping create a better environment for learning….even if it’s difficult to see the connection to that. Support it and don’t undermine it. When parents undermine and don’t support school rules, they are invariably undermining learning, although they often don’t see that.