Stalin once said “One death is a tragedy. Ten million is a statistic.” He was a ruthless dictator, of course, but your bus crash victims were much more of a “statistic” to you than the college shootings, if for no other reason than there are, what, 20,000-30,000 (I’m guessing. Don’t know the actual stats.) such tragedies each year in the U.S. and a much less “personal” killer in that a vehicle was involved, etc. But , I assure you, to each of the affected families, in both cases, the pain was just as real, no matter what the sociopath Stalin said. And you are not an insensitive person either, because one affects you more than the other. The fact that you question yourself on it proves you are very sensitive to the pain caused by tragic deaths. Be satisfied that you were honest enough to confront the issue in your own mind.