Search is, by definition, biased. A completely unbiased search engine is completely useless to everyone. Some result is going to take that coveted first spot, and several results are going to fill up the coveted first page. In order to narrow down all the results and be useful some bias is going to show up. I don't go to Google (or Bing, or DuckDuckGo, or etc) because I want an unbiased search. Precisely the opposite. I go because I think their bias gives the best results.
If Google were unbiased in its search results you would search for tigers and get random results having nothing to do with tigers because maybe that's really the page you wanted and you don't want bias in your search results. Even allowing that every search result has to have the word tiger in it, there's a vast difference between getting the Wikipedia article on tigers vs some random MC Hammer fan-fic that mentions one time that his pants had tiger stripes.
An example to drive the point home: Where are my keys? A biased search would look first in the places I think they are most likely to be, and those places will be biased by me according to what I normally do with my keys, where I normally go, where I normally use them, etc. My keys are more likely to be in my pants pocket than, my wife's, and certainly more likely than some stranger's (though there is non-zero percent chance it could be in any of those). But an unbiased search for my keys would say that any place is equally likely. Even reducing it to all places that a human could have traveled to in the time since I last saw them biases the search by supposing that advanced life-forms with faster-than-light travel took my keys to Alpha Centauri overnight. Plenty of people believe this could possibly be the case, and a search for my keys that doesn't take that into account is biased against these people and their beliefs.
I agree with your last statement, though. Rightly or wrongly, this may cause Google to change which direction they are biased in. It could also just be an opportunity for others to try different search engines to see which bias they prefer, whereas previously they had never considered it.