Google has never manipulated its search results or modified any of its products to promote a particular political ideology ....
Perhaps they think "promote" doesn't include manipulating search results to reduce the visibility of particular political ideologies or positions on particular issues.
There is zero doubt that shortly after PropOrNot issued its list of websites to ban, the search ranking on Google search for those sites went way down. How does Google explain that?
Also, why did the sites disappear from Google News? Many of the sites were in my Google News because I specifically added them to my news results. They disappeared from my news and could not be added back. In fact, Google removed my ability to choose sites with much granularity at all. I dropped using Google News as a direct result of all of it.