I agree with the bottom of this list mostly. Ultimately I like every Seinfeld episode at least a little. but some were weaker than others.
Puerto Rican Day and the finale are generally thought as being among the worst episodes and I can't really disagree. PRD just isn't that funny, and the finale has it's moments but the whole trial section is all lame callbacks.
most of Season 1 is pretty weak cus the show didn't know what the heck it was doing yet. But those are easier to forgive, and they're interesting to watch because of how different they are from the rest.
I can fully get behind ranking the Soup Nazi closer to the bottom. I was never that much of a fan of it. "No soup for you!" is an annoying catchphrase.
Most of their top picks are great. can't complain too much about them.
I never thought the Contest was all that great though. It's always kind of baffled me why it seems to be the consensus pick for best episode. It always just seemed pretty middle-of-the-road for the show. The subject matter might have made it unique and groundbreaking at the time, but it hasn't aged well and it comes across as weirdly tame and awkward now. I don't think that Curb is better than Seinfeld, but Curb would have definitely done this premise better than Seinfeld.