Well, that's a slightly different question.

If the article is on Trump claiming that Google politically biases search results, Google having a history of returning suboptimal results in a way that is "stereotypically liberal" would be some decent supporting evidence - someone having done something before increases the prior probability of them having done so again. If that's actually accurate, of course.

Now, it seems pretty clear to me that this was a bug (and one I see in other, non-political search results) and that lowers the credibility of the criticism. I'd still rather have both sides make their strongest arguments though, and that includes pointing out prior occurrences that might suggest a pattern.