Actually, they probably don’t. I mean, I mentioned the fat landlord on Good Times, but they probably have other friends that were fat whom they dearly loved, and they even liked them being fat!
Always, with people, they don’t like bad leaders, cowards, cheaters, etc., and they’re singled out for harassment, often with cheap shots.
However, a school presents a different problem by default like a prison often does. If someone is a coward, they have to be super-Alpha to get rid of the image. They have to be either a jackass (daredevil) or super powerful in sports or music (like a rock band), etc..
Now the culture in the West is PC, but young people are not and probably never will be. They’re more accepting toward some things, but they will always tend to see “default people” as cowards until proven otherwise.