Ads aren’t payment because it’s not you the user that’s paying, it’s a 3rd party that pays the provider to shove ads at you. Which you can take or leave.
If I go to a store and don’t want to look at the ads they won’t hold me down and shove them in my face. They’re ultimately interested in me buying actual products. But Google’s real product (YouTube Premium) is not a compelling product and the vast majority of people visiting YouTube come for the freebies not the Premium.
So they’ve resorted to feeding you ads by force but you do NOT have to take it. Google can choose to lock everything behind Premium and if you bypass that then that would be piracy. But simply refusing to look at ads ain’t.