If someone treats you like a second class human, treat them the same way back. Take no bullshit.
Are you a short man?
Taller men are physically more attractive. It's the same thing as a pretty girl getting more attention than a plain one. <br />
It's just the world, man.
Yes, it does affect everything, and everyone. I'm surprised that this is a conversation for you, at your age.
How can you say that plain girls are not stigmatized or stereotyped? Everyone is. It's just how the human machine works. We remember our experiences and associated them with whoever or whatever it was with. Everything is discrimination. It takes a discriminating mind to think critically, to behave as society dictates.
Everything goes in cycles, friend. It's nothing new, but it may be new for you. However, I do wish you the best of luck in life. Just try not to take it personally. I don't :)