It's not about fairness, it's about trying to find the right point to apply pressure and create a public discussion.

Both Apple and Microsoft could not care less about how terrible they are in their (ab)use of patents and they particularly don't care how customers perceive their use of patents. Challenging them gives you a zero percent chance to succeed. In fact, they have a lot of clients and customers who might even cheer them on. In any case, they have spent a lot of time and energy to spin this in the past and they would just repeat that pattern.

There is a very tiny chance that you would have success with Google - even if you don't succeed with them directly, you might get the ball rolling on a public discussion. Trying Apple or Microsoft is a surefire way to kill any such discussion very quickly.