>Google has in place limits to stop things like pornography showing up, with it's safe search feature. This is already a form of censorship based on the values of countries like the USA.

You are confusing their quest for relevance with censorship. Google filters out pornography from most search results in general under the assumption that pornography results are not desired. If, however, you do wish to view pornographic content, you can always search for pornography related topics directly, in which case pornographic results will be returned.

Turning on Safe Search, a user controlled option, will try to do a stronger job filtering the results. A notification is displayed that safe search is on, and the user can always choose to turn it off. This is not 'censorship', it is a useful tool for their users.