It’s not censorship if it is a closed platform. Sony can choose to ship whatever they like on the PS3. So, if you want to ship on the Sony platform then, yes, you have to follow their rules. Just like XBox, just like Wii, just like iPhone, just like cell phones, just like network TV, just like hollywood movies in their distribution channel, etc.
Why is it not ethical? They want to put games in their platform that will recoup their investment in building the platform to begin with. How do you expect them to stay in business if they can’t recoup their investment? What you don’t want, on a closed platform, are so many half baked, semi completed or amateur looking games, that it is a barrier for the average consumer. This is why the control mechanisms are in place. If you want free and open access, the PC platform is there.
And to be clear, I encourage game programming on the PS3 that has the opportunity to survive commercially. Do you really think that all of the XNA games being created will be available though XBox Live Marketplace? Absolutely not. Get the tools to all developers and the ones who have a chance for commercial success are promoted.