The first is that there might be a large group of users unknown to you and I who enjoy looking at pinterest in the image results and that is who Google wants to cater to.The discussion is about Pininterest in text searches. My only objection to Pinterest in image searches is that it's paywalled/login-walled.
But larger issue is I'd acknowledge some search results just aren't what I in particular want but I'd claim other results are actually objectively low quality and you seem to want to push things to realm of pure subjectivity, any old crap is something someone might want and who I am to deny to them that pnis enlargement pill.
I would say that the results Google returns involve a number of factor/filters. A. What's considered mainstream, what appeals to many B. What's could be more or less objectively called quality. C. SEO, What results just slip through based on the page spending a lot of time and money appearing like A or B to the algorithm (but not being that).
And Google spends a huge amount of time and money trying to keep C from being the only thing BUT that's still not enough because there's a lot of time and money spent on the other end. At the time, this tug-of-war serves as a moat keeping competitors out. Any Google competitor would have to invest similar amounts of money.
Google has, does and always will make choices about what is best and that the definition of best is up to their discretion.*
I'd love to have a decent Google competitor. But I don't think you have won many friend here by implying that Google's discretion is just arbitrary (as a number of your posts here seem to imply to me). Google won, back when they had competition, by caring a lot about the, uh, quality of their search results. Now that they've won, they're slipping into other things and moreover, the SEO trash are nipping their heels.
Which is to say you won't build Google alternatives on "democracy" but on some concept of quality people will want.