Generally, airports are out of the way from the usual populations that commit these crimes and don't see a lot of traffic from them.
Students aren't unsupervised youngsters with bad ideas as such but not far removed from the concept. The H-Bahn never really looked bad.
Our society is new and in flux. It hasn't yet converged and congealed with a semi monolithic identity (even if from disparate parts). Who knows if it will ever happen. Maybe one day.