They're not talking about paid ads

uBlock Origin can block more than just ads. It has "annoyance" filters, premade lists for cookie popups, and a lot more.

On top of the lists, each user can block annoying things they dislike easily. Just right click the recommended videos section and automatically add it as a uBlock Origin rule.

Can you block recommendations on ublock? I haven't seen that.

You can block anything with uBlock, so, yes. Learn how to use the picker tool (looks like an eyedropper.)