How Do We Know It's Not Terrorism?

From ABC7 Eyewitness News: "'It was nonstop': Survivors describe horror of Allen, Texas mall shooting that killed 8, injured 7. Shooting in Texas involved children, officials said."

Another day, another random killing spree, and endless hours talking about it on the news, giving the next killer the opportunity to see the nonstop coverage HE will get.

There have been been mass killings in a bank, a medical center, a mall,  a school, at parties, on campus, and on and on.  Has anyone considered that this is deliberate terrorism rather than "just" mentally ill or angry people? This is also what terrorists do: target random people in places where they gather in numbers.  Why isn't there a task force to at least address the possibility?