I’ve been pretty vocal that folks need to vote Hillary just to keep this clown out of the White House, and I agree with you that he has uttered some deeply disturbing crap during his campaign.
But this particular quote strikes me as less designed to be taken literally than his other inanity. Despite the repetition, I don’t think he believes or expects anyone else to believe that Obama founded ISIS. He is just being a prick, by saying that, in the same way that I might say, “you know who created the piracy problem? You know who is to blame for all of it? The RIAA and the MPAA. That’s right folks, they’re the bastards who made it so damn hard to buy their content digitally, it’s their fault we have Torrenting and illegal streaming and every other manner of piracy.”
And obviously, that’s just as ridiculous a statement as Trump’s.
But I also take your point that this rhetorical tool which he’s wielding with all of the subtlety of a sledge-hammer, has the potential to be taken literally by those who occupy the far margins of mental stability. Let’s just hope they don’t.