In the wake of the Orlando attack, we have seen the revival of an old debate in which Obama and the left refuse to name this enemy. Either they can't even say the word "terrorist," or they can't use any modifier that implies that Islam has anything to do with it.
After a large and deadly attack such as the one in Orlando, where it was clear almost immediately that the perpetrator was an Islamic (or Islamicist, or radical Islamic) terrorist, it is glaringly apparent that Obama is refusing to call the attack what it is. And this is a weakness that Donald Trump
is determined to exploit, and rightly so.
Does it matter what we call perpetrators such as Omar Mateen? Obviously, both Obama and Trump---coming from opposite sides of the question---agree on the fact that it
does matter, or this rhetorical battle wouldn't be going on. By using the words he uses, Trump wants to signal his resolve to oppose Islamic terrorism, as well as opposition to PC leftist language. What does Obama want to signal? Deference to the Muslim community, emphasis on his underlying policy goal of increased gun control, and minimization of the hugely increased threat from ISIS that occurred on his watch while he poo-pooed it.