Comments like this are ironically hilarious, because the commenter is being critical of the very point of stories; to represent another person in order for them to relate to the story enough to understand the moral of it.
Take the Knight slaying the Dragon archetype, for example: the knight is the social justice warrior demanding equality, and the dragon is the villain hoarding wealth and resources. Now...who do you relate with most out of the two? The dragon wanting it all, or the knight seeking justice?
If you can relate to either on even the smallest level, you understand representation and why it's important.