In-universe acknowledgement of human-alien identical-ness

If anyone is interested Lindsay Ellis (aka the Nostalgia Chick) has an interesting video on how aliens are portrayed in movies.
Designing the Other: Aliens on Film
It focuses on more alien looking aliens, but still worth a look.

Yeah Alex was kinda racist when she said “be Kryptonian” implying their kind is inherently cold and humans are the ones with feelings.

Has anyone in DC, in comics, movies or anything, ever noticed, pointed out, questioned or explained the fact that Kryptonians and many others happened to look exactly human?

Actually, I was just thinking about this idea the other day. It's interesting that Kara made the distinction between being better than a human in 3.01 and that she wasn't a human, she was an alien in regards to how she feels. A lot of the discussion after that was centered on the viewer's astonishment that Kara would make that type of statement. After all, do aliens not feel, too? Do they not love the same way? That, I think, would be a fascinating concept for the writers to explore further (even though I doubt that they will) because the show strives so hard to embrace difference among humans yet, assimilates the actual aliens that are the leads in the show. Why should we assume that Kara Zor-El wants or even needs the same emotional/social things that humans do when she doesn't need the same physical things?

I also think it is interesting that Kara still distinguishes herself as basically two halves - Supergirl and Kara Danvers. I believe that it was after or maybe during Season 1 that the theme was about getting Kara to think in terms that Supergirl and Kara being one in the same and how does she balance the two lives. But, she has mentioned, at least twice this season, that she actually does not see them as the same. I wonder if this is because she thinks of Supergirl as the alien part of her and Kara Danvers as the human part. Does she even consider herself to still be Kara Zor-El? Again, a concept that would be nice to be explored.

As far as how the comics portray the looks of human - my uneducated comic book guess would state that the reason why they look so human is because when they were written they were meant to be reflections of everyday human. They are supposed to represent what an ordinary human strives to be: a hero, with powers that allow them to help overcome adversity, spread goodwill and defeat evil. People relate better to symbols that look like them, hence the humanoid form.

Not really, but in terms of character Superman (and later Supergirl) were supposed to be essentially human. The alien thing is a way to explain their superpowers.
People don't usually demand an explanation for their similarities, just their differences.

Also it seems like the sort of thing that is hard to write into dialog without slowing down the plot, though it's possible that people in universe question that sort of thing off screen.
Right now I'm picturing two stoners from earth 38 having the following exchange

Stoner1: ever wonder why Supergirl looks human.
Stoner2: yeah, and how does she fly without wings
1: she has arms
2: But she doesnt use them to fly. She doesn't, like, move them, and they aren't wide enough to glide on
1: rockets don't have wings
2: yeah maybe she's like a rocket. *farts* sorry dude
1: *gasp* oh my god , that's it man!
2: *giggle* what?
1: *giggle* Super farts!