I would imagine that they are betting that most users will use this to host small static sites with negligible traffic, allowing them to benefit from payed for, but unused resources.
More likely scenario is a tiny PHP site with the database hosted elsewhere?
(Wow, I didn't know you could just serve content straight off the storage. I need to re-examine AWS.. thanks :D)
Edit: nevermind, just saw their TOS
I meant the opposite. They have free reign to censor content.