I don't think the original article was very well researched.
It would have been better to show a pattern than an isolated event.
Also, they used a California democrat and a Texas Republican. Since Google is California the person reviewing may have recognized the local name but not the other.
Or an individual Google employee could be biased.
or two different employees reviewed the ads and one was slack or lazy or made a mistake.
Or maybe Google IS biased but this article doesn't show that.
Certainly not enough to justify a boycot, in my opinion... but it would be interesting to do a more systematic test.
It you did it well and compared various search engines, you could probably generate a great deal of publicity.