It's Google's social network that they give everyone for free, they can refuse service to anyone. I don't agree with the level of censorship personally (it's a little bit too PC), but I respect Google's right to run their website how they see fit.
Of course they have a right to run their website how they see fit. But we also have a right to talk about what they're doing, and make informed decisions as to whether we'll be a part of their social network.
