seen plenty of people not help for similar things here in the UK, but people in the UK love to look down on the "stupid americans". To be fair, most countries have similar views of other countries, oh, thats so bad, that wouldn't happen over here. Jesus, some of the cases going to trial here in the UK make me ashamed of how pathetic they are, and just the same America has the same kind of people looking for money. An objective person could see it happens in both countries, the litigious nature and the apathy to accidents.
People are very judgemental on who and how they'd help. I've seen a kid, years and years ago, i was probably 13-14, a kid who looked maybe 10 came flying out of a park on his mates bike, turned out his mates breaks weren't working but didn't tell the other kid before he tried it out not expecting him to go out the park, came screaming out, almost hit me, straight into traffic, bang. Kid, EVERYONE stopped and tried to help, hell this was pre-mobile phone years so a dozen people all ran to the shops to get help.
I've seen a motorbike get smacked by a car, the guy went flying but didn't get really hurt, but basically no one gave a crap. People simply thought, meh, motorcycle, what do you expect...idiot and walked on.
To a certain degree when theres a crime theres an added reason to not run over, you don't really want to get dragged into it and everyone would assume someone else would call for help, which most likely someone obviously did. Some guy just off screen yells, i'm calling an ambulance, no one else needs bother. Plus, old guy, smacked hard, you really want to watch someone die up close, its not great.
I can see not wanting to get involved, but I would if no one else bothered and would be pretty disgusted with those that just walked past when no one was helping. But this isn't representitive of every situation in the states and those that say anything like it is, are just being ridiculous.