I can't find any source online that says felony assaults on the subway are up 9% this year. Even the Post, which is typically inclined towards hyping crime rates, reports that felony assault rates are flat this year[1]. The same source claims that major offenses have dropped 18% YoY so far.
As with so many other things about NYC, salacious stories are given a funhouse mirror effect: you wouldn't want to fill your car's gas tank next to someone who has a victim in their trunk, but that person isn't being given national news coverage like the corpse abuser was.
[1]: https://nypost.com/2025/04/03/us-news/nyc-subway-crime-drops...
3 hours ago:
https://nypost.com/2025/05/14/us-news/nyc-subway-musicians-f...
New York Times in March:
https://www.nytimes.com/2025/03/14/nyregion/subway-crime-nyc...