So wait, Trump's saying this guys is ('probably'*) ISIS?
If anyone's been paying attention, one of ISIS's stated tactics is to claim credit for anything and everything, even if it has nothing to do with them. That helps them seem bigger and more powerful than they are, creating more fear in their opponents and more support in their backers. It's actually there in their equivalent of the ho playbook.. and Trump is running that play.
Either he's utterly ignorant, or wilfully disregarding the fact.. but he is actively supporting a terrorist organisation in saying that sort of shit.
So Trump gets attacked by a guy that puts ISIS flags on his social media content, and somehow you are trying to argue that Trump supports terrorism? There isn't a big enough Picard sigh gif to respond to your argument. I cant remember the last time I've seen such brainless leftist idiocy outside the comment section of a gawker article. The fact that Trump gets so far under the skin of sjws and other social liberals, to the point that they go full retard like this, might have a bit to do with his popularity...