Sure, we could speculate about his true unstated reasons for marking wrong my answer.
I highly doubt the science teacher marked me wrong for "dumping", though. He had every opportunity to explain that to me after I got my exam graded and I asked him about it. Then he had the opportunity to explain that face-to-face with my parents. He did not do so. He said that while I got the answer right, he was "mad", thus the mark against.
Besides, notecards were not allowed for any part of the exam, and I wrote my answer from memory. I think it was clear that I knew my stuff pretty well and was not "dumping" a bunch of bullshit onto the science teacher.
There was no indication before taking the exam that I would be punished for hurting his apparently-sensitive feelings while giving the correct answer (as he agreed I did). If there were, I certainly would have chosen a different medium for proving my command of the material.
Good experience to prepare you for the rest of your academic and working life where your performance rating will often be strongly influenced the evaluator's current mood or biases. Or the police officer's mood when you get pulled over. Or most other authority figures' feelings when they're making decisions that affect you. It's unfairness all the way until we die.
Authoritarianism, everywhere and in all forms, seeks to shut down curiosity and critical thinking.