To put it differently: I object to your sense of proportion.
In many countries, some jobs are de facto unavailable to short men. Next time you visit a schoolyard. See who the bullied kids are. They might have something in common. It might not be their skin color. It's not talked about a lot because it is taboo. It may be your sense of proportion (haha) that is incorrect.
The mental gymnastics is astounding
Is it immoral (akin to racism) for women to have any preferences at all, or just regarding height?
It's crazy to me to see 5'7" being listed as basically undateable. I'm 5'7" and I'd say a quarter of my male coworkers are shorter than me. Some of them are hispanic or asian, most of them aren't. They don't seem to have any more trouble with relationships than the coworkers that are taller than me. Then again, the happily married man under 35 is not strongly represented in any height range here.