This is how I understand it:
Not neccesarily Americans but it's really about any group or "Movement" that has a problem with something in the games concerning what's typically Japanese as in from a cultural viewpoint - And of course the Japanese themselves ain't budging an inch over it.
However I'd have to guess the vast majority of who's offended are indeed American.
Anything from female characters with over-exaggerated "Features" to whatever else they have a problem with, they complain hoping the Japs will cater to them....
But it's all wasted breath.
Instead of dealing with them, the Japanese just keep it at home and do as they do, things they know would be an issue they don't release here and yes, alot of the censorship is mandated too by the gov and Nintendo itself has to play along.
Had to do a bit of research to find an example and came up with the following:
There was controversy about a game called "Atelier Ryza" a few years ago that had SJW's going after it over the appearance of a certain character in the game and saying the main character was a problem too.
Of course the Japs didn't listen and as long as it was "Legal" they didn't change a thing about it.
This is the newest iteration of the game and yes, the fanservice is still there as the following makes perfectly clear:
Atelier Ryza 2 review: Ryzing to the challenge | FULLSYNC
Alot of what's in it is actually based on what's popular in Japanese culture and that does drive sales in Japan so....
I mean - There ya go.
EDIT:
As to if that was a factor in MS not buying Nintendo at the time, only those guys can really say.
If it does happen it does and you'd probrably see the effects of it in short order.