Re: 616 Cap was created and written by WWII vets for a majority of his defining years ...
Yes, but his creators also considered Steve Rogers an exceptional man. No one here (although yes, I have seen it elsewhere) is saying 616 Steve is unrealistic; just that he's not typical of his time.
And Ult Steve is still pretty progressive; he dated Jan, showed no difficulty taking orders from Fury after the initial misunderstanding, and is fairly close friends with Sam and Tony (half Hispanic). There's a bit in the Ults annual when he gets quite angry, and tells Sam he didn't fight WWII so people could carry right on being racist jerks, and Sam is all *sigh* all right, you missed sixty years of progress which is a decent excuse. I will explain some stuff to you. And Steve listens, he's not a dick about it.