I agree with the others. This has ALWAYS been present, and random. Heck, check out Nero if you want to find a nut case that killed many people for no purpose AND ruled ancient Rome.
Then there were the crusades, where many women and children were killed for their religion, in addition to other atrocities.
I agree, the difference in present day is that #1, we have media coverage, and #2, society has changed the value on human life so much, that we CARE now.