I wasn't saying that Facebook should be regulated like shopping malls. I was saying that people who say that private censorship is not problematic, do not have an answer for things like internet.org. Facebook are legally free to set up programs like this, but people are also right to criticize Facebook for setting up a system that takes away from the freedom of the open internet. The shallow analysis of the XKCD comic ignores these issues, yet I often see that comic posted when people complain about left wing censorship online.
A daily comic isn't the medium that one usually chooses for subtlety or depth. A lot of people complaining about "left-wing censorship" (or "right-wing censorship", for that matter) are in serious need of a clue-by-four and wouldn't bother reading a deep analysis if it were given to them.
But people complaining about "corporate censorship" are smart well informed people? How is internet.org controlling what website people get to see different from, for example, YouTube controlling which videos people get to see? And how are the whims of whoever will control or influence internet.org different from the (mostly left wing) groups that (sometimes successfully) pressure companies to remove material from their websites.
