Even from their example, you can see the political bias clearly in the first pic. I believe that they believe themselves have an unbiased algorithm which creates this result, which they believe is unbiased.

However, it is clear to me, their result is definitely biased. I do not believe an unbiased algorithm will generate a top list of covering on the supreme court decision on the travel ban only includes reports from NYT, WP, The Atlantic, Chicago Tribune (the only right), CNN. I also do not believe an unbiased algorithm will generate a list of other top stories from only Politico, NPR, WP. So In a list of nine titles, only one right media (Chicago Tribune) got a shot, but not Fox News or WSJ. Not even CBS, ABC which are kind of centrist.

Of course, an argument would be that most of the media is left. But don't forget, the left / right split among the American voters is not that extreme. If you generate a list of new reports, which one is more unbiased: A) represent the perspective of journalists (90% left), B) represent the perspective of voters (60% left)?

My experience with Google News is that, if you do not manually customize new feed, you will get mostly from NYT and WP, almost never FN or WSJ. You will also get a lot far / crazy left stuff from Huffington post, Daily Beast, Mother Jones, but you will never get national review, not to mention breitbart.