Well it's because by this logic we should just stop Americans from studying for computing jobs as well, that way those who remain will have higher wages. Just as the Luddites tried to stop the rise of industrialization that threatened to bring the skills they used to employ to the wider public at lower costs.
The real answer is that immigrants create enough economic demand to be net positive even for Americans, for much the same reason as Americans are generally more prosperous when there's more of us.
Seriously, you live in some dumpy parts of the country and you can have the exclusive rights on being the town cloud guru locked down and in principle get higher wages in a smaller labor pool, but for some strange reason few of us want to do that.
The real answer is that immigrants create enough economic demand to be net positive even for Americans, for much the same reason as Americans are generally more prosperous when there's more of us.
Seriously, you live in some dumpy parts of the country and you can have the exclusive rights on being the town cloud guru locked down and in principle get higher wages in a smaller labor pool, but for some strange reason few of us want to do that.