Imagine you're the copyright adjudicator for this claim at YouTube. You don't know if the claim is accurate. If it is and you leave the content up, your employer might be fined, and you get a write-up from your boss. If you take the content down, no fine, no write-up.

What would you do? Even if you try to side with creators, you might eventually be let go for making too many mistakes.

I understand that YouTube doesn't adjudicate claims themselves, but I think this may explain why they don't. Their adjudicators are heavily incentivized to take everything down. As a result, YouTube is hands off.

If this is an accurate framing of the situation, then incentives may not be properly aligned. Alternatively, YouTube (and others) simply have a monopoly position that needs to be out-competed.