I think many engineers would gladly say that Cambodians deserve to, and should be paid a lot more.

Your argument is also a comparison between two different economies.

The comparison here is between two groups of people living in the same country, even working for the same company. I did the math at a previous job - the CEO would make in 20 minutes what I made in a year. Would that CEO say they I should get paid more?

Also, many CEOs in the US might make what they do precisely because the laborers in Southeast Asia make such low wages.