More than likely it's just some whackadoodle with a gun but we can still call it "terrorism" as it has much the same impact and effect as a targeted act of terror has...
@Vin53 What difference does that make? Whether they're riding the subway, shopping at Walmart, eating at a restaurant or watching a movie in a theatre? It is a deliberate attack on human beings, no it's not targeted at any specific group but it's still terrorism:
Terrorism: "The unlawful use of violence and intimidation, especially against civilians, in the pursuit of political aims. So the only difference is the "in the pursuit of political aims"
@spjennifer My guess (and it's just a guess) is this, especially if it turns out to be the 62-year-old suspect they're looking for; You'll find a history of work-related failures (lost job, disciplinary action, lay-offs), a divorce or widower situation and likely grown children. This is a man who has, for years, cataloged grievances and curated a revenge list that got so detailed it eventually just ended up being mankind, so he decided to punish the accused. He'll turn himself in because he's got no relatives to assist him or he'll see the end coming and take control of the one thing he feels he has power over. And yes, that's terrorism when it results in a mass shooting. You're spot on about that.
As someone who served for 35+ years and in many war zones, I can tell you that it is something that exists in certain types of characters and I have seen and served with some of them. It is unusual and the Military usually weeds out people like that but I could see where there would be people with similar character traits in civilian society. I have taken lives when it was necessary for survival but to be able to do that indiscriminately to seemingly innocent civilians is beyond my scope of comprehension and probably has more to do with mental illness than anything. I suspect you are correct in that this is an individual with a grudge to settle against those he feels "wronged" him in some way and is now settling the score in similar fashion to the people who "go postal" but the fact that he attacked random people in a subway instead of targeting specific individuals is what makes this "terrorism" in my mind, despite the probable lack of a political or religious motivation...