Some rules are better than none at all. Just because there are edge cases doesn’t mean the rules won’t work for 99% of cases. Same thing goes for “certified” sustainable forestry or fishing. Could some people cheat? Sure. But that doesn’t mean that having processes in place and rules to follow won’t work.
Both Google and Facebook were caught breaking the rules when it came to using internal certificates and were having users install privacy invasive apps.
While you're not wrong, I think it's a fallacy to say that just because people break the rules doesn't mean we should not make rules. Lots of people get speeding tickets, that doesn't mean we should abolish speed limits.
Companies break rules, they get caught, the rules get changed and improved and hopefully things tend to get better (in theory).
I agree with making rules. But since developers as a whole can’t be trusted and there are technical ways that Apple can enforce to ensure that the rules aren’t broken (in most cases), I think they should.