I'm not seeing the "you're a woman and I'm threatening you" anywhere. "By the way I designed cool t-shirts, you want one?" and "Lets not have any bad vibes due to this", doesn't sound like "Do what I want or I'll kill you."
Maybe the guy is selfish, and intensely trying to "make it" (sounds like a young over-eager tech guy), but he's not threatening to attack or "victimizing" due to sexist views imo.
If someone disagrees, please provide one shred of evidence. As best I can make out its summarized with the big-text quote midway through:
"He didn’t use all caps. He didn’t swear. He didn’t yell. All he did was calmly… threaten. Subtly… insinuate. And distance himself from reality, little by little."
I'm not impressed, the bar has been raised for claims of harassment and victimization. If you had spent your whole weekend working around the clock on a project that won the prize on your own code, only to be told your dreams were now crushed because you "weren't a good fit", you'd probably be begging to find a way to hold onto the tickets or the project as well, whether your boss was male or female.
[Edit] And also, the mentors, the coordinators, the others in the posts all seem to agree that this isn't harassment. This really points to an issue with hackathons in general. You have people contributing to a "startup", then getting tickets to an expo, all without any contracts, just some verbal agreements -- these type of disagreements are bound to happen.