"Obama's attitude was a "slap in the face" to voters in five states yet to hold nominating contests, and millions of Clinton supporters, the former first lady's communications director Howard Wolfson said."
Obama's assumption is that KY is going to be the last "big win" for Hillary (Puerto Rico will not be "big"). He will win handily in Oregon, Montana and South Dakota. After tomorrow, he will have accumulated enough of the remaining pledged delegates to make it impossible for HRC to overcome it. He can declare that he has reached that threshold and no one should be able to say a thing.
Furthermore, when someone reaches that magic number (2,029) before ALL of the states have had their chance, that does not mean that the winner is delivering a "slap in the face" to the remaining states. It just means that the system has delivered is a candidate based on the nominating system and rules set out by that party.
The slap in the face is not coming from Obama. The slap in the face is coming from the Clinton wing of the Democratic party that refuses to acknowledge Obama as a candidate that has outraised, outdone, and outperformed TH on every front.