An explosive-laden SUV or Ryder-truck that had a good "run up" to get speed would do far more damage than someone intentionally crashing a C150... its hard to crack 100mph of airspeed flat out in level flight in one of those.

The pilot's license will likely be pulled for good. I am certainly glad they did not shoot it down, though... its nice to see some restraint exercised in a case like this.

BTW, the C-150 is most often used as a primary training aircraft for people to become initially licensed in.