> If you tell the user exactly what they did wrong, they will keep trying by changing very little in the original video until it gets past bots, but still keeps the illegal or "forbidden" message.

I think there's a possibility to implement that handles the issue you describe.

It's trivial to detect an user trying to circumvent content controls if he's trying that from the same account. When that is detected the user account can be put into manual mode review or automatically block new uploads for a while.

If circumvent is tried with different accounts the current system already doesn't prevent that so nothing is lost.