Because the people who voted for her in May probably wouldn’t be voting for her in November:
One thing to keep in mind is that many of Kentucky’s “Democrats” are Republicans for all practical purposes. Interestingly, registered Democrats still far outnumber Republicans 57%-36% (that’s as of 2006, though Republicans are gaining). But despite the party registration totals, Bush won the state handily 60%-40%.
Ideologically, many of these people are simply Republicans — but they still got to vote today. Sure, they sometimes vote for a Democrat on the state or local level (just like Massachusetts elects Republican governors). But they consider themselves conservative — and no Democratic candidate who could win the median Democratic voter nationally would be acceptable.
I’d like to think that these Kentuckians vote Republican because of the GOP’s robust economic reform agenda for poor and working people. But the truth is that it’s a mix of cultural distaste for liberals (and their causes) coupled with the failure of Democrats nationally to clearly explain why their agenda helps working people financially.
So let’s keep these votes in perspective. Yes, Clinton beat Obama pretty bad. But this was hardly a “Democratic” primary as most people understand it. I’m sure some funky things would happen in Republican primaries too if they consisted of enormous proportions of Democratic voters.
Meaning that Kentucky is the Democrats’ version of New Jersey. A state they aren’t going to win with the candidate they’ve got.

