Some of this in movies, though, is just expediency. Aliens land in and attack, say, England because, well, it's an English movie. There were movies that acknowledged the rest of the world for global scale events, usually through a quick cut-away to some stock footage of the United Nations (or a quick tour of various cities, with title cards, as in DESTROY ALL MONSTERS* or INDEPENDENCE DAY), but in the end the action is going to center around where the main character lives, and the main character is almost certainly going to live in the country of film production (for ease and budget of setting, if nothing else).
I'm not sure I agree with "when we create a blank human, we make them, by default, American, and when we make a blank human culture, that too is American.", especially if the definition of America is being "violent and independently minded" - and I'm going with film depictions here. The majority of economies in the world are based on Capitalism (in one form or another), and America is seen as the pinnacle of Capitalism, so there's a generalization right there that seems to say "America = the world" but doesn't, really. Almost all, if not all, cultures, have armies and police forces, fights wars and experience crime. Almost all cultures, if not all cultures (my Anthropology studies peeking through) have a somewhat xenophobic or at least "wary of the different" element, from basic primate programming if nothing else. Any number of Italian, British and Japanese sci-fi movies hinge on the idea of "violent humans react badly to alien encounter" - heck, all of Gerry Anderson's CAPTAIN SCARLET series is based on it, as is the conclusions of CHILDREN OF THE DAMNED, and probably one of the takes of QUATERMAS, off the top of my head. It's a cultural staple from THE DAY THE EARTH STOOD STILL (and parodied effectively in MARS ATTACKS), if not earlier, and evolves out of the realization of what the cold-war mindset was doing to us. To put it another way, if you remade E.T. in South Africa or Jamaica, I don't imagine the movie still isn't going to feature the authorities coming after E.T., whether they be a government or local police force. In fact, the reverse trope is easily as prevalent, the "well-meaning scientist" who's always blurting out "we have to try to communicate with them", even as the thing is eating his skin.
As for "how the aliens talk about us" - maybe there's something like what you're looking for in Stanislaw Lem, perhaps? or ALIEN NATION (movie and series)? I can't imagine, in globe-spanning stories or scenarios in which we're privy to the alien's thoughts, that there aren't any "here they have many things and consume more and more of them, while here they have almost nothing and can barely survive making all the things for the ones who consume more and more" type overview scenes. ("But I don't own slaves" she says and The Doctor says "No, but who makes your clothes?"). On a smaller, regional scale, you get into the almost unavoidable possibility of charges of propaganda - a scenario in which aliens achieve contact in the Middle East and offer up an alien-eye's view of the conflict is going to probably be picked apart by both sides of that conflict, regardless of how nuanced a depiction it makes. And if it's so generalized that no one complains, then we're back to the default setting of "barbarous and paranoid", which I don't really see as a default American setting (and believe me, there's no knee-jerk nationalism at all behind that statement, as I'm the first to think the worst about us).
I guess I see what your saying in the idea of say "aliens arrive in Sweden" and the Swedes don't immediately blow them away, but a lot of that has to do with the particular scenario as sketched by the creator. The "boat people" aliens of ALIEN NATION end up becoming third-class citizens in America (I can't recall if they were in any other countries), which says something about that particular view of American culture, I guess. THE MAN WHO FELL TO EARTH might be another avenue to explore, or BROTHER FROM ANOTHER PLANET.
And on that note, let's exit on Bowie:
"There's a starman waiting in the sky
He'd like to come and meet us
But he thinks he'd blow our minds
There's a starman waiting in the sky
He's told us not to blow it
Cause he knows it's all worthwhile
He told me:
Let the children lose it
Let the children use it
Let all the children boogie"
*As a quick aside, here's the really interesting, non-alien thing about GODZILLA films - while arising out a symbolic embodiment of the atom bomb, Godzilla and all the other daikaiju end up also generating a series of films where Japan - which in the real world wasn't allowed to have a standing army after WWII - *has* a standing army equipped with high-tech beam-weapons and the like. So the Japanese audiences were allowed to get pumped up (Akira Ifukube's great music for these films were almost all marches) in scenes with a mighty force rallying against the invader... even though said mighty force was invariably crushed and trod upon and blasted out of the sky. Interesting psychology there.