When it affects your bottom line by changing ranking factors then it is no longer as optional as you make it out to be.

Google decided to dominate the search world, and it now underpins a huge portion of online businesses. That comes with a level of responsibility to be fair to it's patrons that in this particular instance I feel isn't being met.

Of course they can do whatever they want, it is their product, but we don't have to like it.