George Lucas - Why the Vitriol?
Watch "A New Hope."
Then watch "The Phantom Menace", pay particular attention to any scene with Jar Jar Binks in it, literally noting every. Single. Thing. He does.
Hell, let's go a step broader. ANH is something of a coming-of-age story about a young man teaming up with a mentor and a roguish anti-hero to save a princess and along the way stop and an evil empire! Stuff happens! Action, fights, space-battles, humorous quips with surly antiheroes!
TPM: Something about trade blockades, taxes and Senate procedures.
While Jar Jar was the worst character of all time, C3PO was rather annoying in the PT as well. Plus, Lucas had the sense to get rid of Jar Jar for Clones and ROTS, yet people hate those movies as well.
Also Phantom Menace can also be described as a movie that shows how an inefficient government can be exploited to gain terrible power - a theme relevant in today's world. Lots of people did "the right thing" and ended up doing awful harm. The movies might not quite be modern mythology like the OT, but they are not all fluff either.