Except many of the 38 "witnesses" didn't witness anything. No one saw the entire attack. Few saw any of it. Most only heard bits of the incident, and to them it sounded like a couple having an argument or two rowdy drunks on a Friday night. And no, Genovese wasn't screaming for half an hour; her attacker quickly punctured her lung. So while this case proves that dozens of '60s New Yorkers lacked the initiative and enhanced senses of Spider-Man, that's not the same as people all being indifferent to the suffering of those around them.
Oh, and even with this limited view of the crime, two separate witnesses did call the police. This was before 911 services went into operation, so calling the police was a bit of a pain in the ass. Also, one of the callers is believed to have been gay, which gave him every reason to distance himself from New York City police in the '60s. Also, an elderly neighbor came to Genovese's aid despite not knowing whether the attacker had left, cradling Genovese in her arms until authorities arrived. Maybe people sometimes dodge responsibility, but this case in truth demonstrated the exact opposite point.
So how did we end up with a story about 38 people suddenly finding their shoes very interesting when it came time to help? It all goes back to a sensational New York Times feature that ran two weeks after the until-then-obscure crime. How the article came to be is a long story, but in short, the reporters involved knew it was a crock, but didn't want to risk their careers by challenging editor Abe Rosenthal, who insisted on including all the outlandish details.
The psychological community knew about these inaccuracies for decades and dropped the Kitty Genovese case as a teachable example, even as it remained a popular urban legend. The Times owned up to their mistakes 52 years later when covering the death of Genovese's murderer. So at this point, "Genovese Syndrome" should be the name for when people parrot old myths to look cynical instead of bothering to check basic facts.