The point at which I disagree is when you imply that this is somehow comparable to institutionalized slavery and Jim Crow laws.
They didn’t equate racism and discrimination based on height, they said that there’s no difference in someone discriminating based on that - meaning discriminating based on something that wasn’t a choice and cannot reasonably be changed.
It doesn't hold because:
1. I pointed out this distinction in my initial comment, and the OP has not conceded the point that "x and y are members of set S" is different from "there are no differences beetween x and y".
2. This in turn negates the "best meaning" you seem to be assuming.
And the first point bears repeating. Even if height discrimination and racism are both instances of prejudice based on immutable characteristics, there are very important differences between them.
Your waiving of the rulebook in response to this is puzzling.
> Even if height discrimination and racism are both instances of prejudice based on immutable characteristics, there are very important differences between them.
I meant what I said. You claimed that one of the differences between heightism and racism is that "The shortness of men (barring outright dwarfism) has never been the object of widespread theories about their fundamental inferiority". That claim is blatantly false. Why did you make it?