I respectfully disagree. While the idea that the cast of
Seinfeld are awful people is regularly put forward (including by the show's own finale), it always rung hollow to me. Yes, they're often shallow to the point of conceit, but villains?
Kramer was in an AIDS walk. George saw a security guard standing all day and wanted to give him a chair. Elaine was concerned that a shopkeeper hosing down the sidewalk in front of his store was wasting water. Jerry helped Bania with his (Bania's) comedy routine, despite finding him personally annoying. There are lots of little examples scattered throughout the show of the cast members doing nice things for people, simply because they feel moved to do so. While they also have their awful moments, they're essentially ordinary people, with good and bad days, simply a bit more outsized for the sake of comedy.
Of course, none of that applies to Newman. He's
definitely a villain.