I don't think you've understood the lesson here. Chesterton's fence is not about keeping systems in place. It is about how you approach changing the system.

I understand it. Just like the precautionary principle, it’s bad epistemology and bad advice.

It doesn’t provide any guidance on how much research is necessary before removing any specific fence. The most charitable interpretation is “don’t remove a fence until you do a sufficient amount of research into why the fence was built,” which is tautological and useless.