When ads for instance are not allowed on Google, all that's left is google's opinion on whats useful. Which is weirdly enough most likely less free and more opiniated.
Google bans categories of ads, and bans advertisers that it views as bad actors, the same way it does with search. It also uses an algorithm to figure out what ads to show you, the same way it does with search results. It uses a lot of the same data (location, history, preferences, etc) to make those decisions.
The only difference I can see is that advertisers pay money to influence that algorithm (ie, a company willing to pay more money will win an auction against a company that has less money). Is that what you're referring to as the thing that makes it more free and less opinionated?
Doesn't Google currently own one of the biggest advertising platforms on the entire planet, and don't they curate what categories of products are allowed to appear on it?
There are lots of problems with curation, but I am not convinced centralization is one of them. At least, I'm not convinced that centralization is any more of an issue with curation than it currently is with advertising. There's no reason to centralize curation and give control to one company/government any more than there is reason to centralize Internet ads with one company/government.