Comedy is not universal, and Seinfeld's comedy certainly no exception. As someone who is almost phobic of embarassment and misunderstandings, I absolutely hate Seinfeld given that the core for many of the jokes in the show are the characters misunderstanding a situation so holistically that they are put into embarassing siutations. Sitting through an episode of Seinfeld literally makes me queasy.
If you honestly think that just because you and many others loved the show, that means that suddenly your subjective onion turns into an objective one, you should really take a step back. You liked the show. Great. Doesn't mean the people who didn't like it are wrong.