TBH what I'm picturing there is, someone probably told Trump once that the US government created ISIS (because it literally did, at first, and later created room for it to grow) and he just thought that... well, because we didn't hear about ISIS more than a few years ago, it was Obama's fault.
Edit: basically Trump's wrong in a relatively narrow sense, historically speaking. Future historians probably won't distinguish much between Reagan's Operation Cyclone and Obama's drone assassination campaign. They'll probably look at the Reagan-Bush-Clinton-Bush-Obama-Clinton-Bush block as a cascade of stupid crooked things done by stupid people to avert stupid problems, much the same way we don't really distinguish between the 'good' and 'bad' emperors when talking about the fall of Rome. Like I'm sure Anthemius wrote some good civil planning laws, but that's not making up for the rest of it.