Sour grapes is a frequently misapplied cliche. It comes from the fable about the fox who was trying to reach a bunch of grapes that were too high up for him. After numerous failed attempts, he gives up and rationalizes that he doesn't want them anyway, since they were probably sour. So it's meant to mean disparaging something that you can't have (or someone - "she's probably a bitch.")
To the degree that we have sour grapes over something Kentucky related, it's over recruiting. We wouldn't want their top recruits anyway, since they are all one and done, would ruin chemistry, etc. which frankly hasn't really happened for them. They've had off seasons, but they haven't had attitude problems - or at least any worse than anyone else's. But I would say though that the sour grapes expression would work better if someone like Vandy said it - a place that hasn't actually won. We've ended up finding our own grapes, so whether the grapes we missed out on were sour isn't really all that significant. Saying that we like our system better where we develop talent and see out players improve over time isn't automatically sour grapes, because it's worked. But saying "I didn't want Briscoe anyway - who needs his attitude?" is very much so.
There probably is too much Kentucky obsession here (they've taken over the Duke spot at the top of our angst meter). But if they were doing this under a different coach, we'd probably be more rational about it, since we've suffered at the hands of UK exactly zero times (unless you really wanted to win that game at MSG).