How is it an "example for a topic of liberalism in academia?" What makes you think you got relatively low scores because the scorers were "liberal" and disagreed with you? You're not doing yourself any favors going down this road. You wrote a poor essay and got relatively low grades that reflected that. End of story.
Instead of having a chip on your shoulder at such a young age, learn how to write a correct essay. If you write one like this for a college exam you will fail and deservedly so. And it won't be because the professor is "liberal".
Did you read this article on unwarranted self-esteem? Not entirely relevant to your post but you are laboring under similar self-delusions, albeit yours is a reflexive political defensiveness that ignores the fact that your low grade was deserved (and could have been lower).
Don't handicap yourself like this. Learn.
I'm not trying to handicap myself. It's just a hypothetical topic. Please don't put words in my mouth.
I think his point is the fact that the test is evaluated in a subjective manner. It makes it no more valid than an evaluation at some New Age seminar. The system which the educrats produced is broken, and their tests are essentially broken.