The worst teams in baseball are the Red Sox (Pedro Martinez attacked Don Zimmer on the field) and the Atlanta Braves (John Rocker's infamous rant against NYC).
If you're gonna argue like that, you must include the Reds (The Cueto/LaRue incident), Giants (Marichal/Roseboro), and White Sox (never forget 1919). Point is, every team has a bad moment. And to your other point, I've lived in New York City my entire life and I can't stand the team and their asshole supporters. And I'm totally cool with the Mets.