Flipping genders in this case doesn't work on multiple levels.
But I also think that if the crush reacted with fear and/or disgust to a male showing his junk, it would absolutely be humiliating and debilitating. Especially if he was to show himself in the same way - meekly, desperately, from the position of submissiveness.
True, a simple flip won't work. But I am trying to think of a way for a male to submissively show his dick to an uninterested woman, and I am just not getting anything... maybe at a hot spring in a nudist camp?
Her: "Sorry, but I must turn down your offer of a date. I just don't see how you can really be attracted to me."
Him: "Ah, but Booboo-san, I am attracted to you."
stands up "See?"
Best I can do. And no, I don't really think the above would work 90% of the time.
Returning to this story: is this sexual harassment? No, she doesn't have, say, a promotion to withhold from him if he says no.
Was her act threatening to the MC? Based only on this one scene, no, she hasn't threatened him. And yes, men are stronger than women, so the girl student simply doesn't pose a credible threat (assuming her behavior doesn't get worse) as a man would.
But should you, a guy, be concerned if a woman does this to you in CURRENT_YEAR?
Oh, hell yes, because the justice system is effed up and believes all kind of nonsense (like "all women," heh) when it comes to female harassment. If this girl goes off the deep end, MC could have his life ruined.