Lucas says he doesn't care about critics, but with the onslaught that Episode I brought he pretty much has to say that, to save face. He's human and we all know if a human being was in his position and there was so many people saying he is a terrible director and writer, and his fans are even making websites and petitions to get him to stop, that has to hurt. And in fact he has admitted this, under the properly candid conditions. But what can the man do? All he can do is basically try to roll with it and say, "well, who cares about their opinion anyway." But he hears his critics, and he knows, sort of, what they are saying. Lucas makes these films for an audience, contrary to what he says ("I make them for myself"--no you don't George, you make them for an audience and you make great pains to the best of your ability to ensure the audience enjoys the film within the context of your storytelling goals). I'm quoting the exchange below from memory but I'm pretty sure this is verbatim:
Leslie Stahl: When critics go after your directing, your writing--it has to hurt.
George Lucas: Oh it hurts. It always hurts. It hurts a great deal. But part of directing is that you get attacked, sometimes in very personal ways. [goes on to his green-house/white-house analogy]
And of course, Lucas dropped out Jar Jar Binks almost entirely for the following two films when he was a main character in Episode I. Some people say, "oh, his part in the story was done, where would he fit in Ep. II/III". But please, really? You don't think if Jar Jar had been the hit Lucas was hoping that he would find a place for him? He didn't have a place at all in the prequels for the droids, but he forced them in deliberately because of fans, because their characters were hits, even to the point that his rough draft of Episode III didn't even have R2D2 and C3P0, because he couldn't think of excuses to include them in the plot. Fan/audience/critic pleasing is also why Boba Fett is in there, and half the other OT references (Han Solo was even in the first draft of Episode III). In fact, Lucas outlines to ILM artists that critics complained the Episode I Yoda looked fake, even though he was technically more advanced than in 1980, and so it was really important to make Episode II Yoda match the originals ("Puppets to Pixels" doc).
Lucas not only listens to his critics, but he sometimes changes the films to please them. But he tries to save face, he's stubborn and doesn't want to seem like he was "wrong" so he denies that critics/audiences matter, that he makes the films only the way he wants. But nobody that is human or in the business of storytelling would believe that. And contrary to the brave front he pretty much has to put up, for the sake of his own dignity--the sting of critics hurts a great deal and that's why he tries not to put a lot of attention on them. But he still does care on some level about what they say. He's well aware of things, whether it is online gusher-basher wars, fan edits, or what the media is reporting. His rather advanced state of knowledge about all of this alone shows that he does keep tabs on all of these things. And of course in the link that inspired this he says he doesn't want to make more Star Wars because they just receive criticism. If he didn't listen to critics or fans or whathaveyou then why would that matter? But it does matter, he not only has bitterness over the criticism he gets, but it's so severe that it's discouraging him from the idea of making more films.