A Mex programmers subredddit r/taquerosprogramadores has plenty of stories about that.
Maybe it's just the structure AZ has established for Mexico. No idea.
If it helps you, I have one counter example handy: I have had an excellent Indian manager.
Racism emcompasses a bit of a different scope, including policy, institutional structures, and norms, of which stereotypes is directly related to norms and can be indirectly influential on the others.
However, the comment I originally reacted to would be definitely qualified as being "raciste" by most French speakers (and be illegal in France)
As for the legal part, calling all people of a given origin "bad managers" is definitely illegal here in France (once again, speaking only about what I know of)
If we were to believe that structural racism was the only kind of racism, we'd be forced to conclude that people can't be racist because people aren't structures.
But it's precisely the opposite as structures are composed of people and racist people are often the reason we have structural racism.
I even had a great indian engineer who emigrated from India (his parents are still there) who actually complained about Indian work culture.
It's like myself when I complain about mexican culture (for work, ethics, corruption or mediocrity)... I know that not everyone is like that, but shit where I'm from (southeast Mexico, Campeche) you'll be lucky to find someone that breaks the stereotype.
And I've several friends still there.. I just don't like the education and vslues society imparts us there
My hypothesis is that a part of what you're observing is just some form of 'survivorship bias' - changing jobs with visas isn't easy (been there done that) so folks are more willing to 'bend' to the culture being driven internally than just moving out (esp. with the long wait times).
At some point, its hard to distinguish the people from the culture, and what came first, but that's a different conversation.