Are you missing the “the hawks in our party who...”?
He is blaming it on specific individuals who supported a particular policy (indiscriminately giving weapons to Sunni Islamists) and who also happen to be in HIS party.
Basically, he is pointing a finger at McCain and Lyndsey Graham, whose criticism of him prompted this statement on Morning Joe.
“ISIS exists.... because of the hawks in our party”
He is blaming it on a political party, the republicans.
Not the democrats, not Obama, not the left, “our party” created ISIS.