To take a specific example, maids in India make about $3 a day. If they had the opportunity to move to the US and do similar work at say minimum wage that is at least a 10-fold increase in their earnings. While the cost of living in the US is much higher than in India, its mostly because the quality of life here is much better. Back home she probably lives in a tiny shack in a slum with no running water. If she lived in the US college-dormitory-style, it would be a massive upgrade of her living conditions and still allow her to save money to say give her children a better education.
So what we're weighing here is $1000 reduction in the wages of some of the most vulnerable Americans against a life-altering opportunity to the most vulnerable global poor. I don't really see how Borjas (or anyone else) can pick the side of the Americans in this ethical dilemma.
Take another example. Say a college educated Indian female decides that she is sick of the sexism in India and wants a better life for herself. Using the large amount of resources online she teaches herself programming and becomes as good as people who graduate from coding bootcamps in the US (so not a stellar programmer but a net positive with proper guidance). Her primary competitive advantage is that she's willing to work harder and for lower wages than the Americans graduating from coding bootcamps. Requiring that she be paid the same (or more as many commenters have suggested) prices her out of the market.
So the choice we face is whether we allow her to work as a developer for say $40k a year which she would vastly prefer to being stuck in the shitty circumstances of her birth at the expense of perhaps reducing wages for American programmers from say $70k to $60k a year. Again I don't really see how this is a difficult ethical decision.