Of course, people get randomly assaulted on the subway. NYC isn't that safe.

However, every time someone gets assaulted on the subway these days, it's in the news, complete with cellphone camera video from multiple witnesses.

Back in the 1960s, when violent stuff happened, there was not much record of it and it didn't get into the news unless it was particularly bad.

Perception has really changed, along with information technology.

Your problem is you're watching the news, don't do that. (The rate of news articles is pretty much never connected to how much crime there actually is.)

NYC is more or less the safest place in the world; it's certainly the safest place in the US. And the remaining danger is getting hit by cars, not in the subway.

It wasn't like this in 1990.