They're probably just trying to be sensitive to their audience and sponsors. Google also censors pornography because a subset of users are offended by it.
Scott Adams' mild political satire is understandably censored because it is comparable in offensiveness to porn?!
By the way, Google doesn't censor porn. They categorises it. If they were either dropping all porn or replacing all porn images by pictures of little ponies, that would be censorship.
Censoring pornography doesn't infringe anyone's human rights.
1. Define human rights
2. Provide a methodology by which they can be objectively known.
Is a right to be left alone to one's culture a human right? Is a right not to be deprived by outside powers of one's native language a human right? And who gets to set the limits on the outer limits of such a right? (i.e. is the right to advocate the position that genocide of, say, black folk, is desirable a human right? What about pornography?).
My own sense is that usually these have no epistemology behind them and are based solely on projecting one's a priori assumptions onto the world.