Having spent many years as a college instructor, I've learned that if students don't respect the assignment/test, they won't take it seriously.
I know that's how it seems to a lot of people - I indicated in my very first post that I realize a lot of people (including many right here on the BBS) just love that scene. All I can say is, it didn't strike me that way at all. He didn't seem a "little" immature - it was like a high school stunt. It was a lot immature.
Fair enough. If that's how it struck you, that's how it struck you, no arguing with that.

I understand why you would think that, that's obviously one way to interpret that. But keep in mind, mature people can do immature things if they want to make a point, and that doesn't make them immature people, even if they act silly to point out how silly something is.
Again, an example from my life: as a graduate student in English, I was taking a teaching composition class. We got what I considered an absolutely absurd assignment: we were to draw a picture and use it to explain/analyze the writing process. Not a diagram, but a picture, like a tree or a coffee maker. We had a rather hippie teacher.

Anyway, at first the assignment enraged me, I felt it beneath me—I was a graduate student with an A record, a serious researcher! But then the punk rocker came out of me (I was also a performing musician). So for my image, I drew a rather pornographic image, then spent the essay analyzing it academically, sure to point out at the end that I felt my image was no more absurd than the assignment as a whole. Perhaps not my most mature moment, but I still graduated with an A average and went on to teach college English...careful not to give silly assignments.
Point being, I can definitely see a mature and ready for command Kirk being at first angered by the test, so he takes it again and is frustrated by the test...and then decides to "take the piss" as the English say when he signs up for it a third time. Remember, he listened to the Beastie Boys as a kid, maybe there's just a little punk rocker in him too!
