Americans tend to speak their minds more freely than others. Just in general, we tend to speak what's on our mind, and that can create some discomfort and confusion. When I run design meetings, I really have to call on engineers who are non-Americans to speak up, otherwise, they won't add their contributions. Now, it might be language barrier, or cultural upbringing, but I saw this in Europeans as well as Asians.
This cultural issue with management tends to bring up "whiteness", but most middle management in Finance/Tech are older white males, many of them are totally awesome, but majority of them lack cultural understandings and "offshoring" can create massive frictions.
The American culture may have worked in an in office environment where you have a lot of body language and non verbal cues to recognize that the "confrontational" behavior is actually supposed to lead to positive results. Besides, meeting in an office, and getting lunch with your colleagues nearly every working day and going for happy hour every week or so means that your relationship isn't defined by the confrontational experiences. How well will it work in a "remote first" environment where you rarely/never meet your colleagues outside the work environment and don't have non verbal cues, and your confrontational behavior simply make teammates uncomfortable isn't clear yet.
On the other hand, organizations are well aware of certain cultures being non confrontational, and have done a lot of work in actually helping them speak their mind without being confrontational. Pre-pandemic when I became a manager, my company provided me with a ton of training on structuring meetings and brainstorming sessions in a way that encourages everyone to participate.
There's a very good argument to be made that in a remote first environment the "confrontational" culture would lose out, whereas the "non-confrontational" culture, which can easily be worked around through a variety of management techniques, will work much better.
I think the same culture would pervade anyone who is 2gen and greater American. Unless someone is 0-gen or 1-gen, they become Americanized (as any immigrant to a new country would become localized after 2 gens elsewhere). So unless they are recent immigrants or the children of those recent immigrants, even if they are not white, they would be culturally American.
On a side note, I think 1st gen have it the hardest of all. 0-gen know their standing and know they are newcomers with foreign customs. 1-gen often are in the middle and aren't sure where they belong culturally, here, or there. 2-gen usually don't have any such ambivalence.
This cultural issue with management tends to bring up "whiteness", but most middle management in Finance/Tech are older white males, many of them are totally awesome, but majority of them lack cultural understandings and "offshoring" can create massive frictions.