The Red Sox lost, in my order of guiltiness, because:
1) Clemens wimped out of Game 6 early, complaining of a "blister", but really he was just not ready for the big-time pressure as the game built to its climax. Clemens lied about it for years, but in my view that was simply more proof that he had a guilty conscience about it.
2) Buckner intimidated McNamara (and McNamara allowed himself to be intimidated) into allowing Buckner to stay in for the 9th, instead of coming out for his usual defensive replacement. Buckner wanted to be on the field for the "glory picture" where the catcher, 1st basemen, etc, charge the mound and embrace the pitcher at the final out. Buckner was a surly jerk then and McNamara backed down.
3)McNamara uses mediocre pitcher Al Nipper in Game 7 in relief, who get hammered -- as if McNamara forgot that you don't use your normal rotation in Game 7. He had starters on the bench, even Clemens, to throw in in relief. Nipper was a disasterous choice.
I could go on...