Here is the thing, the article title might be misleading.
He later died at a hospital after many of the 50 to 70 teens who gathered nearby recorded the bloody attack and made no attempt to stop it, Nassau County police said at a news conference Tuesday.
The title is suggesting that no one tried to help. Then the article says many did not attempt to stop it while others recorded it.
In reality, when something jumps off, most folk are not going to jump in to breakup a situation. Also, there is a lot of value in having multiple people recording an incident. There is a record of the incident and the perpetrator, which will help the investigation.
I feel it is unfair for the NY Post to label those kids as being that self absorbed, when their actions is fairly indicative of what you will find in any group of bystanders. A few will aid and cheer the perpetrator, some will try to interview to help the victim, others will spectate, while some will pull out their cameras and record.