I don’t think that they are even very bad. They just aren’t… Good. Sure some of the dialogue is awful, but there’s worse. It’s bad enough to keep them from being good, but not so bad that it makes them terrible. They are terrible if compared to esb, but that’s not saying much not many movies can survive that comparison.
I’d argue there are MANY films as good or better than ESB. And I say that as someone who for a very long time held ESB as far and away my favorite film ever (some other films have caught up with it in my favoritism but it’s still easily in my top 5 or better). But there’s a reason it’s rarely included on lists like the AFI’s top 100.
Second, the prequels are BAD movies. On so many levels that I can’t begin to understand people who try to argue they’re not. It doesn’t mean you’re a terrible person or stupid or any awful thing like that for liking them. I love lots of bad movies. I have a real soft spot for 50’s B movies and I unabashedly love Godzilla and other giant monster movies. But I can acknoweledge that many, even most, of those movies are bad movies by any reasonable criteria. I can understand why people criticize them or don’t find them enjoyable. Doesn’t stop me from loving them inspite (or often because) or their badness. But I’d never try to argue Plan 9 From Outer Space is some brilliant piece of high art with numerous layers or depth and meaning. THAT would be preposterously silly. Just like that ring theory nonsense…
If you think the prequels are anywhere near as bad as those then I don’t know what to tell you. I even said I don’t think they’re good, but equating them with plan 9 from outer space or a 50s b movie is crazy.
Also, esb is on quite a few lists, including the one you mentioned.
ESB is not on either iteration of AFI’s top 100.
And yes, the prequels are every bit as bad as some 50’s B movies (not to mention some b movies are actually quite good). Perhaps Plan 9 is a stretch, but I was just using it as an example to illustrate my point. But while the prequels may have had higher budgets and better production values (to an extent), the writing, dialogue, wooden acting, bad direction, some AWFUL special effects shots, complete disregard for continuity within the series, etc are all every bit as bad as crappy B movie from the drive-in era.