The atomic bombing of Japan didn't happen today, it happened nearly 80 years ago. Plenty of people consider it a war crime to this day, and plenty of people excuse it, but it's difficult to be horrified by events old enough to barely exist within living memory.
80 years are not so far in time for me as I recently realized that when I was born I was closer to the end of the war than my current age. That made me feel somehow more connected to that past event than to the present.