> The author may not _like_ that these are trusted, mainstream, popular sources

Because that's not what I'm searching for. Even if we all agree all the Russian sites are propaganda, I still want to be able to search through it. It's a political decision by Google to filter out these results. It's not algorithmic because no matter how precise your search query is, you will never get results from certain forbidden domains. Google just directly removed rt.com from results recently, so even if you search for "rt.com" you will not see it. I'm sure they have similar filtering based on certain keywords.