I see this argument again and again, and quite frankly I have to agree with Zuckerberg. People are dumbasses! Not the people you refer to though, but rather the people constantly making said argument.
How much do you think it costs to host a site like Facebook? Servers, storage, electricity, bandwidth.. Facebook is massive, and the simple fact of the matter is they have to generate income to sustain their existence, regardless of your blind ideologies.
That being said, I'm not a huge fan of ads or information gathering, but I'd rather have a small text-based Google ad informing me about online electronics stores, robotics and other somewhat interesting stuff than the huge Flash obscenities of old!