Also if he acted as a lone wolf is this really an act of terrorism or a hate crime? I understand the question is semantic and doesn't change anything but... If he acted alone out of rage over seeing gay men kissing then this seems more hate crimey. I mean if someone were an ISIS/PKK/Chechen/FARC/IRA associate or sympathizer and lashed out violently killing several in a road rage incident would it be terrorism?
He pledged allegience to ISIS. The "lone wolf" narrative misses the point. Organizations like ISIS, aided by the Internet, spawn these sorts of "lone wolf" attacks.
Obama is not blame for this - no more so than our ineffective federal agencies at large - but he will bear responsibility for many more attacks in the future. Obama has actively pushed to import hundreds of thousands of Muslim immigrants en masse, who as a result of such block migration will not assimilate, much as what is currently occurring in Minnesota with the Somali community, and it breeds radicalization. As Trump says, we need smarter immigration policy. Granted, he's a ducking moron, but at least he recognizes we have a problem.