They're not actually ad blockers. They are javascript exploit protection. It just so happens a good fraction if not the majority of exploits come in through ad systems in general. It's a rare thing a website itself is going to attack you. It's always some code/media imported from a third party domain/ip. ie, ads.
I can't tell if you're being sarcastic? YouTube ads are served by Google, just like the rest of YouTube. You can verify this by looking where your network requests go in devtools.
(I used to work on ads at Google, but in a different area and don't know anything about YouTube beyond what I can see in devtools.)
