This doesn't come out of nowhere. Klein's book, Blood Feud, spells out the bad relations between Clintons and Obamas.
Subsequent to the 2012 election, Bill Clinton followed up with President Obama on the deal they had made in which Bill would help Obama get reelected, while theoretically Obama would for one thing place Clinton’s handpicked political allies in the DNC — including replacing Debbie Wasserman-Schultz as its chair. Obama did not follow through. And in a post-election phone call, the following occurred according to Klein:
“‘Obama cut right to the chase,’ Clinton’s associate continued. ‘He said he wasn’t prepared to turn over his campaign’s digital operations, data mining, and social media juggernaut to the Clintons. Instead, he said he was going to fold that operation into Organization for Action, his second-term political pressure group. Hillary would have to build her own data and analytics system. Bill listened, said, ‘Okay,’ and let it go at that.
‘Then Obama said it was too early to make a decision about 2016 and who he was going to support of the Democratic Party nomination. He wasn’t prepared to back Hillary now. He was keeping his options open. He was reneging on his promise.
‘Bill’s blood began to boil. He was speechless with rage.