The prequels are bad, because they have made us look for problems everywhere. They set a bad precedent for how star wars fans should behave.
I put most of that on Lucas, not the films themselves. Had he only made the bad films, the two camps may have been less venomous. Still divided perhaps, but possibly more along generational lines or style preferences. Instead, Lucas set about dividing the fans into teams with all of his CGI revisions and lying about the 1970s.
He created the division where you either like the real Star Wars or you like the 1977 theatrical Star Wars. For deep fans of the prequels, that was license to criticize the fans who were liking Star Wars incorrectly. He created that fire and continued to add fuel to it until he jumped ship and left the huge mess behind.