Ben, kids these days are immature and don't act up when they should. Many don't do anything becuase they've come to expect "it's someone else's problem" or "someone else will do it". If not then it's a general lack of consideration for others (take the boat of teens on dad's boat powerturning when there's other folks trying to ride, throwing huge wake passing right next to fishermen, beating on the boat in general, etc.)
By your profile, I'm only a few years older than you and even a lot of my friends who are my age are that way, while other I know have grown up a bit.
I find it hard to ignore someone who obviously needs help, and I know a lot of folks (I'd wager most on this site) feel the same way. Over the years I've seen a lot of inaction and indifference on part of the younger kids compared to older folks. That's what I mean, and age factors in simply from my observations of when someone needs help and who acts. Perhaps I'm wrong.