If you only receive immigration from only one country, it is easier for these newcomers to associate and become a political force that can change your status quo. Whereas if immigration is diverse, this situation is more complicated.
>Texas
>USA
>All of South America?
All of the Americas?
That sort of thing could honestly be in the minds of the Powers that Be.
The positive spin for diversity in where your immigrants come from is that it is better for the culture if the participants have diverse backgrounds.
This does not make much sense. People get green cards, not countries. Imagine if you were at the DMV and each region of your city had its own queue. People coming from the smaller parts leave in 5 minutes, and people hailing from the larger parts have to wait 8 hours for their turn. It's their fault for living in a more populous place?
What did the people in the smaller areas do to deserve their faster queue compared to others, except being born at a certain place?
Work visas should be about the person who passes the interview, is selected and is able to hold said job.
Imagine if there was a company with a white CEO who was only hiring/putting other whites into high level positions because they happen to be in a majority white area. If that makes you cringe, you should have the same reaction regarding this.
Diversity = various countries/peoples around the world getting a fair chance
Not diversity = Only Indians get work visas
If 90% of a town is white and 10% is black, 9:1 is a fair ratio for executive boards on average. Anything else would mean that the probability of a person holding a board position given their race would be different for different races. Imagine if every company in Mombasa was required to have an even split between white and black: being born white would guarantee you any job you wanted because you would be competing with less than 1% of the population, while in contrast every other ethnicity would be crowded in to half the number of jobs. In fact if racial quotas were instituted in Kenya and every race was given the same percent quota, 98% of Kenyans would be forced to be unemployed.
Diversity is generally considered a positive thing for companies and countries. Also there have been complaints that US is poaching the best people from other countries so diversity helps moderate that.
The US sets US law to serve US interests, so I don't see how that would be a motivation.