Mating preferences are certainly not discrimination.
They are a personal decision, a mind set. Simple as that, in my opinion.
The most important moment is when you get to know each other - in a very short time, you will check out that person, head to toe, body language, character, what not. This can (and probably will) include height, weight, body shape, body language, and much more. In some cases, a preference might become unimportant, if everything else is perfect. Flexibility wins.
„ they only want tall men but we are enraged if men state, that they only want skinny women
Are we talking about women who have a certain expectation but who cannot fulfill the requests of the desired man? If so, where is the problem? Move on, find a man who wants you!
With my athletic body shape and some curves I am definitely not skinny, so if that would have been Mr. ZeeTee's "killer" preference, we might not have become a couple. I might have been disappointed for a moment, but that's life, no? But, it turned out differently, we share so many things - and we soon fell for each other.
Our modern world is full of hipocrisy, women are supposed to be tall, slim, beautiful, with nice boobs and butts, men should be tall, strong, have lots of money and what not. Welcome to the modern western society. In the end, it will be what you make out of it.
In my opinion, it is much more some social media platforms that promote discrimination. Just think about most "influencers" who definitely do not live a normal life. And many human lemmings follow superficial role models, ideas and thoughts promoted by these people.