Facebook is the only reliable or affordable form of internet access at all. I think the measure of "own website" changes once you reach a certain mass and especially when that "own website" is not a personal website but a corporate one. Not to mention the government influences that can and are made against these corporations.

It gets morally messy when you consider scale. At what point does it cross over from reasonable moderation to censorship? If Facebook were a country, it would the largest country in the world. Is it okay to censor two billion people because Facebook is not an "official government"?

I'm not against moderation at all but at a certain scale does it cease being only moderation? I would argue yes, but at what point? That's trickier to answer and I can't really say I know.