What should we learn from Hugo Tale-Yax, the homeless man in Queens who lay dying on the street while no one stopped to help?

This seems to be the feel-bad-about-humanity story of the moment:

Hugo Alfredo Tale-Yax’s last act may have been helping a woman who was having an argument with another man last Sunday morning in Queens. But his last hour or so was spent as a curiosity for people passing him on the street as he lay face down in blood after being stabbed several times.

Mr. Tale-Yax, 31, was pronounced dead by medical workers who responded to a 911 call around 7:20 a.m. on April 18. The police confirmed the authenticity of surveillance video on The New York Post’s Web site that shows dozens of people walking by Mr. Tale-Yax, who was homeless, lying on the sidewalk at 144th Street and 88th Road in Jamaica. After more than an hour, the video shows one man shake Mr. Tale-Yax before turning him over to reveal the wounds.

This Metafilter thread about the story shows a wide range of different reactions. The standard response is that this is like the famous incident with Kitty Genovese, who was stabbed (also in Queens), and slowly died in public as many people failed to help. (I'd be remiss if I didn't note that this account has been seriously called into question.)

This supposedly shows the "bystander effect": people don't help someone in distress if there are many other people around. (Incidentally, this is at odds with the conventional wisdom that seemingly altruistic behavior is actually done out of a self-interested desire to appear benevolent: people are apparently more likely to be good Samaritans if there's no one watching.)

A related reaction is that the Tale-Yax incident is even worse than the Genovese incident:

For the first time in history, most of these people could have called 911 using an object in their pocket. Most people fundamentally suck. You've just got to try to be different.

Another reaction is: we shouldn't castigate the passers-by, because they probably had no idea what was going on. Tale-Yax probably just looked like an ordinary homeless person. Yes, he was lying in a pool of his own blood, but his body may have been covering up the blood. A Metafilter commenter elaborates on this:

I'm sorry, but when you are walking early in the morning and see a homeless man face-down on the sidewalk (a not-infrequent occurrence), you assume they are passed out drunk, because 90% of the time they are. You don't stop to see if they're okay, because that can turn into a dangerous situation if they awaken still intoxicated. I say this as a social worker who genuinely cares for the plight of the homeless and understands that the majority of the time their circumstances are caused by mental illness that they didn't have the resources to treat. But, I'm also a person who cares for her personal safety and lives in NYC and would likely have walked on by too, not assuming the worst.

It's also worth considering this commenter's experience:

I'm a woman, and I've been threatened by homeless dudes in various states of inebriation/mental confusion a few times in NYC. Just for walking too close/sharing a subway car. It's as terrifying as you expect, and pretty much removed my willingness to go up to homeless strangers and help them unasked.

But my favorite reaction is this one from another Metafilter commenter:

I guess the way to reconcile this is to say: the problem isn't that people walked on by without calling for help, and from this we can conclude that people suck; the problem is that it is so common and unremarkable to see human beings so totally destitute and outcast that they are, for all appearances, lying dead in the street, that when one of them actually is dead, because he has recently been murdered, nobody can tell the difference.