I don't believe that this is specific to men. If an individual is threatening over email then it is more probable that they will be threatening in person in gen

I don't believe that this is specific to men. If an individual is threatening over email then it is more probable that they will be threatening in person in general. If Mark's behavior made the author feel threatened then she has the right to avoid further interaction with him. But as others have pointed out, the emails sent are not threatening in the way that the author describes them, and there isn't really any evidence of "harassment". The author describes Mark's "intensity" while working with him at the Hackathon. It seems likely that this intensity carries over into the way he writes emails as well, which made the author feel unsafe.