This criticism shouldn't apply anymore. They predict categories you like and you can select a category. The 'All' page should be a mix of all categories, not just cat videos. Amazon on the other hand...
I'm sorry I don't know how to turn it on. When I go to youtube.com, at the top it has about 15 categories that it has gleaned from my use (e.g. Guitar, Flight Simulators), some of which I'm surprised it learned, as well as All, Mix, Trending. I use Edge and I'm logged in to YouTube.