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.

Treat you like what? Where was the threat in the email? Did he call OP a "bitch", "slut", etc? Did he belittle her? He asked her for his share of the prize and said that if she didn't then he would pursue it unilaterally.

Since when did that mean he was going to physically harm her? Sorry, I believe sexual harassment occurs in the tech industry and should be stamped out, but this is not a case of it.

Tis is NOT a case of sexual harassment. He might be unknowingly threatening (best case scenario, the one i believe), or downright manipulative, either way she do not want to work with him. He joined her on the project and she offered to give him 2 of the 3 tickets then he started his passive-agressive emails. I got those from people i worked with too, every time i just left the project (mainly because it was never mine). This type of passive-agressive behaviour exist very much in tech, mainly because this behaviour is related with self-entitlment and goes well with smug personnalities.