Yes, a film reviewer establishes the merit of a film based on his own subjective opinion (though he did review relatively, taking the movie's intended audience into account). What, do you think review isn't subjective? He enjoyed the film and found it deserving of merit, in his opinion. His biases showed on rare occasion, but on the whole his opinion was a fairly trustworthy bellwether.
Your continued thwapping on his score of the film that you oh-so-despise betrays your obvious fault in that you only cared about his reviews when they weren't to your liking, because anybody who's read Ebert for any length of time knows that he hated the scoring and added it against his will. All of his scores must be taken in the context of the review, and he always said (nay, demanded) as much. In the context of the review, you know, the words he wrote describing his experience, we find this:
[...] the characters in "The Phantom Menace" inhabit a plot that is little more complex than the stories I grew up on in science-fiction magazines. The whole series sometimes feel like a cover from Thrilling Wonder Stories, come to life. The dialogue is pretty flat and straightforward, although seasoned with a little quasi-classical formality, as if the characters had read but not retained "Julius Caesar." I wish the "Star Wars" characters spoke with more elegance and wit (as Gore Vidal's Greeks and Romans do), but dialogue isn't the point, anyway: These movies are about new things to look at.
It's almost as if he understands the film's flaws or something! It's a completely different perspective when you consume his opinion as it's meant to be consumed. He spoke out very strongly, all his life, against people like you who walked away with the score as a conclusion (for good reason, obviously).
I originally said all that and replaced it with "Your comment sucks.", because I knew you'd fight with me on this, even though it's entirely pointless. I am aware this is Hacker News, but thank you for the patronizing reminder. Your comment still sucks. Your followup sucks, too, particularly the "go back to Reddit" tone (the irony of a person describing Roger Ebert as "useless" on Hacker News, then pulling the Hacker News card to criticize my comment is not lost on me).