The Phantom Menace I'll happily agree with. That was shite. Attack of the clones and revenge of the sith were both excellent. Both better than return of the jedi and empire strikes back. My opinion.
And some people think Steps are better musically then The Beatles or that Transformers is better than the Godfather.
Those people are also extremely wrong. You seem to be under the assumption that all film is subjective when it's not, there's an objective quality to the craft of filmmaking and on a purely technical level let alone on a scripting or editing level, the prequels weren't just bad films compared to literally two of the most celebrated sequels of all time, but they are just bad films overall.