> Imagine a world where literature was preoccupied with height.

Smart of you to have picked one of the few human characteristics that hasn't been used to justify discriminations and very unfortunate historical events... In our world it's not just literature that is very preoccupied with skin colour and gender.

> It wouldn't mean the complainant finds short people objectionable in themselves, but simply that they don't think height is a defining part of reality that all of literature is obligated to address.

You have it reversed, if it's not a defining part of someone's reality, why would one even care whether it's addressed in fiction or not? The person I was answering to does care, a lot, to the point that swinging one way or another can ruin their experience.

Not getting into how we define what are valid complaints vs invalid, because that's besides the point.

You'd find it exhausting. People similarly find the race and gender preoccupation exhausting. Your justification for the different treatment seems to be "for these categories, people are obligated to not find them exhausting, but not for other categories." But that's not well-motivated.

In a height-preoccupied literary world, can you imagine objecting to the height preoccupation? If you did, how could you justify it, if it's not a defining part of your existence?

"one of the few human characteristics that hasn't been used to justify discriminations"

Of course it has. That notions like “Napoleon complex” circulate in pop culture, suggests that society broadly considers short-statured people to be somehow disadvantaged and, moreover, it can be funny when the short-statured kick against the pricks. Also, the demand that a suitable male partner ought to be over six feet tall, is absolutely widespread, both in match-seeking profiles on online-dating platforms and in dating fora where women give advice to each other. (Or, if you want to reverse the sexes, Truffaut’s gag in Baisers volés about dating a tall girl, wouldn’t work if people broadly didn’t feel that there was something weird about this.)