Certain people -- some of whom are in positions of enormous power -- just do not give a damn about other human beings. A certain head of state in Syria comes to mind.

I'd also say that your ability to care about other people, along with overall sanity, will diminish under constant stress. That's why "Preserve own sanity" is #1 on my rules to be followed in case of sudden world domination list and something I need to stay aware of even in my current (and normally not that stressful or important) job.