That's what I'm trying to say - the problem is that I don't see any way to disprove either assertion: "Google is manipulating News" or "Google is not manipulating News"

There is evidence that Google has acted in a partisan† way in other areas, though, which is what makes the assertion worthy of consideration.

†: "partisan" might not be the best word here. "Ideologically-driven" might be better. Google has acted in its capacity as a content host to suppress content that it finds inappropriate, even though that content was benign. Example: https://www.bloomberg.com/news/articles/2018-03-21/youtube-b...