I don't necessarily prioritize my preparations based on "the odds". If I did so, there would be no reason for me to carry a compass while hiking. The chances of getting lost in the Colorado drainages where I hike are miniscule (to get out - "walk downhill, and don't cross any high elevation ridges" - you don't need a compass for that). But I carry one anyways.
Preparing for a "campus shooting" is not specific to campus. It is also applicable for "department store shooting", "grocery store shooting", "movie theater fire", etc.
For anyone to say, "the odds are against this happening to me", while an accurate statement, is an incredibly dumb one. So my goal during one of these incidents will be to surround myself with as many "it won't happen to me's" as possible to serve as a human shield and diversion.
Each to their own reasons for preparations. I base my mine on odds.
The odds are low that I may have a heart attack, but do I have an ambulance follow me around just in case of that minuscle chance I am not in cell range and cannot summon help?
The odds are low that I may be shot in a grocery store, does that mean I should worry and fret and wear body armour just in case for that next time I saunter down to the local grocery store?
I live in a volcanic zone historically known for eruptions. Should I be prepared for a 1 in 200,000 year chance of being near when and if the volcano erupts again? Maybe I should be more prepared and sell or move my house 300 miles just to be safe. Afterall, it would be "incredibly dumb" for me to not think "it won't happen to me" and I will be then used as a "human shield" to protect those who are more prepared.
On the otherhand, I carry a PLB while out hiking. Why? Because the odds of me falling, getting injured and requiring rescue are much more likely then having a heart attack or getting shot at the grocery store or getting buried under hot lava. By the way you do carry a PLB while out hiking, right?
It really comes down to perspective and that every person's idea of risk/odds are completely different in a 1001 different scenarios and it is "incredibly dumb" not to respect that.