I didn't think it would be right to rain on the parade of those who have been writing on the "Yoko Ono appreciation" thread, so I'm posting here instead.
The anti-Yoko sentiment has little to do with whether her artistic output has had merit or not. That's merely a question of personal taste.
It also doesn't have much to do with the fact that the Beatles broke up (at least, it shouldn't). The band had run its course.
And no, it doesn't rest on a lack of appreciation for all the good she did Lennon. Yes, it gave him something to live for ...