Back here, I said I had a post brewing on this topic.
The way I see it, there are three major ways fan authors are depicting Captain America's adjustment to the strange new version of America he's found himself in.
1) He adapts with no problems at all, other than a tendency to not get pop culture references. This pretty much always includes an very modern attitude towards sexual behavior. At the most extreme, authors who take this route have Steve falling into bed with anybody who wiggles their eyebrows at him, and picking up new technology almost as easily as Stark.
I feel that short of changing him into a villain, this is about as far from Captain America's character as it's possible to be. Luckily most of the fandom seems to agree with me and it seems to be the least common depiction.**********
2) He can't adapt at all. It's too new, too busy, too selfish and hedonistic for someone as straitlaced and moral as Steve Rogers. At the far extreme he can't deal with women or minorities in power, the idea of people being open about their homosexuality freaks him out (much less the idea of marriage equality), how comfortable people are with sexuality in general grosses him out, and he even loses it when people swear around him.
I feel that while the less extreme versions of this might
hold true for "random 1940's guy dumped into the 2010's," in general it's only a slightly more accurate a depiction of Cap than the first one is. Helping the underdog is just too much a part of his personality for me to believe he would freak out when society starts to think that maybe there shouldn't be underdogs at all. The most extreme versions of this depiction are almost as rare as (1), but the milder versions are a lot more common, and bleed into (3).
This one seems to come from a combination of authors mistaking Steve's lack of first-hand sexual experience for prudery and a misunderstanding of the 1930's & 1940's. Just because the movies of the era that are still available are mostly pretty clean doesn't mean that everyone's behavior was all the time. As my grandmother said to me once, people are still people no matter when they live. All that changes is how public they're able to be about it. **********
3) Steve is frequently surprised and confused, but once he wraps his mind around them he thinks most of the changes are for the better, or at least neutral. To me, this version is the most true to character and thankfully it seems to be the most common.
Captain America really is Captain Steve Rogers of the US Army
, and I guarantee that even if he wasn't getting up to shenanigans himself, between his time with the USO and his time fighting in Europe he had plenty of opportunity to witness as much as he cared to and probably a bit more. He led an elite unit that was racially integrated and worked with/dated a woman officer who outranked him. As I said above, he stood up for the little guy every chance he had, even when he couldn't actually make a difference, and I just can't picture him disapproving of wider society catching up.
I'm never sure how much sense this sort of post will make to other people, so I might do some editing to clarify things. I'll try to note it if I do.Edits: 6-7-12; 9:37am
I made a few formatting and punctuation changes that hopefully will make this a little clearer.