Re: "He hates the French..."
But operation Rebirth was only about physical perfection. It didn't change his frame of mind other than possibly enhancing his ability to think. 616 Steve has his attitudes because they were always his attitudes.
I'm not saying I approve of the attitudes, I just like the idea of a version of Steve that actually seems like a man taken from the 40s. 616 Steve rarely if ever seems out of place in modern time, and when he isn't it's usually just for gratuitous angst, and the charaterisation will vanish as soon as it's inconvenient. I don't mind it in 616 Steve because he's been thawed for about a decade now (in-universe), and has had time to adjust. Ult Steve has not had nearly that long, and has spent most of it with SHIELD.
(Also, I know it's common usage, but using the term Lowest Common Denominator like that always seemed wrong. Especially since in math, the LCD is a higher number than the one you start with. Greatest common factor is a better term for the concept you mean.)