I think the law in NY does not allow "feeling scared" as a valid reason to initiate physical action against someone else. I think the word is "threatened" and that there are specific components to what constitutes self-defense (which is clearly where anyone is going if they claim JN was killed for "threatening" people). If we all got to kill people who scared us, the world would be a very different place. People obviously have different thresholds for fear, for one thing.
The NY statute actually says "menacing" behavior is illegal (so a citizens' arrest is possible and the menacing person is committing a crime). However, the menacing action is specifically defined as:
Note that it states that the menacing must be directed toward an individual (not a group of individuals). If an individual on that train had actually said, "Please help, this person is scaring me" before DP took action, I think that would help his defense. If he himself felt in fear for his life, well, a jury is going to have to apply the reasonable person standard as stated in the statute. The reasonable person varies from place to place, NYC has its own trials and the jurors will use standards embedded in their own sense as reasonable persons in NYC.
If JN committed a crime, it would have been Third Degree Menacing (no showing of a weapon, only words and actions). It is a misdemeanor. If JN seemed to direct his "I'm going to kill someone" (whatever phrase that was) at one person or even a few people (it cannot be someone far enough away not to be directly threatened), perhaps that's menacing.
Self-defense is supposed to involve enough force needed to stop the threat, and no more. These are things juries are asked to decide. So for DP to use self-defense effectively, it seems to me he has to claim that he acted on behalf of the frightened woman (and there better be testimony from her and from others that she was making her terror known and had reason to believe JN was specifically directed those words at her). It is my understanding that she was sitting down, and that JN was standing amidst the straphangers. How could DP know which of them were terrified? Were there discussions he overheard? Because if not, then he can't claim he acted for the defense of others or in self-defense. IMO.
I don't know what makes feelings "valid," feelings are feelings. We just feel them and many are involuntary. But "feelings" are not a reason to assault someone physically, as DP did. Self-defense is the legal reason. If DP had to get in between JN and this older woman, in an attempt to get between an obviously frightened person (hopefully she was asking for help at the time, if self-defense is to be claimed) and a threat. He still had no legal right to exercise anything more than the amount of force needed to make that woman feel safe again. The way it's judged at court is, again, by the reasonable person standard. If a person is constantly terrified, for example, it's not okay for others to go around killing everyone who terrifies that person.
It's the reasonable person's fear of threat that matters. So if the woman felt individually threatened, the jury will have to hear why she thought she personally was targeted by JN, how JN looked at her or moved toward her and tell the jury how close he was standing to her (he had just got on the car and was in a crowd by the door, so I doubt he was actually looming over her - but she would likely need to have a reason to give the jury as to why she thought he was specifically threatening her). Otherwise, we get way more altercations on trains and vigilante justice. Her feelings matter to her, of course - and to her family/friends. But "feelings" are not valid as an excuse for murder in a court of law. "Speak up" is one of the pieces of advice people are given when something in public scares them. Did she? How did DP even know she was scared until she spoke afterwards? Were they sitting near each other and talking? If so, that changes the whole scenario quite a bit.
Fine line.
Link
edition.cnn.com
