I once set about reading every Captain America comic in order since his revival in the 1960s. There's a stretch of issues where he was basically homeless, living in a series of seedy hotels before eventually hitting the open road on his motorcycle. Every now and then, he would bemoan his lack of home, family, and any sense of stability, and I would get annoyed and ask "Then why don't you just rejoin the Avengers and live in their mansion?" And then I thought to glance at the original publication dates. They ran from 1967 to 1970, making this the absolute perfect metaphor for the state of the country at the time. And it ended when Cap officially partnered up with The Falcon, a black man. Stan Lee, I will never underestimate you again! — Lexi Dizzle
Steve Rogers was a scrawny kid who tried to join all services before becoming the greatest American soldier of World War II. Take away the Super Soldier treatment and the shield, and you get Audie Murphy.
For added hilarity, the Captain America comics actually predate Audie Murphy enlisting in the Army, and he did read comics as a teen and preteen when he got the chance, so there's a possibility that Captain America helped inspire him to join the service.
The fact that the Ultimate Marvel version of Captain America has displayed a Cheese-Eating Surrender Monkeys attitude towards France seems to come out of nowhere, at first; after all, it's a fairly modern attitude. However, part of what makes Ultimate Cap a Darker and Edgier take on his mainstream counterpart is that he doesn't just hold to the good aspects of 1940s cultural mores, but also to neutral and even outright bad ones, such as My Country, Right or Wrong... and bigotry. Let's face it, for all the bravery of the French Resistance, there was a lot of real-life resentment towards France over the fact they capitulated and allied themselves with the Nazis early into the war (not helped by the fact that Britain and America both historically hold animosities towards the country — somewhat hypocritically, in America's case). How many "good American soldiers" has Ultimate Cap seen chewed up and spat out trying to reclaim France from its own corrupt government? That's not to say Ultimate Cap couldn't or mightn't respect the bravery of the resistance fighters, but it's actually kind of understandable he'd be disdainful towards the French as a whole. Given that Deliberate Values Dissonance is supposed to be part of his "thing", it's no surprise that he's supposed to be a Noble Bigot.
There's been complaints about Cap's costume being an inaccurate representation of the American flag, though considering the Flag Code, which states that the U.S. Flag (as in the flag itself, not a stylized representation of it) can't be worn as a costume, as well as Cap's own duty as a soldier, it makes sense that he wouldn't violate the Flag Code by making his costume a direct representation of the Stars & Stripes.
Cap's ahead-of-his-own-time views concerning race, ethnicity, religion, and sexuality are pretty much justified by the fact that he saw first-hand how bad bigotry could be as he witnessed the Holocaust first hand, something noted on the main page. But he's also rather ahead-of-his-time concerning gender roles (or at least, now he is; back during the 60s, not so much), which is harder to explain as women as a group weren't forced into Concentration Camps unless they were part of the many groups that Nazi Germany was seeking to destroy. Except, it took Steve quite a while before he was allowed to serve during the war, and so would have had to stay behind and work in the civilian sector which, at the time, was largely populated by female workers who picked up the careers left behind as all the men were off fighting. Of course Steve would respect women, he saw first hand that they were just as capable as men were at working; combine with then having Spitfire within the Invaders, and Peggy Carter in the French Resistance, showing that women were also capable of fighting Nazis with the boys, it makes sense Steve wouldn't question the sight of female superheroes.
The whole concept of Captain America: let's fight the Nazis, and everything they stand for, by taking a blonde-haired, blue-eyed guy and making him into a supersoldier! Wouldn't it be more appropriate to choose a Jewish soldier for the program?
Perhaps the Jewish creators of Captain America realized the Unfortunate Implications of a "revenge" subtext of that. My take on it has always been that they made it a blonde-haired blue-eyed guy because they wanted to say "Hey, your 'master race' isn't even on board with the program."
At the time Captain America was made, I don't think it was widely known just how far the Holocaust had gone. They knew Hitler was antisemitic, yes, but not that they were being rounded up and exterminated—and at that point in history, "antisemitic" really wasn't something that was unpopular, even in the US. "Blond, blue-eyed supermen" was the physical ideal for the US at the time too. But all the same, the irony was probably on purpose in a, "I've got your master race right here," sort of way.