I could contend that the shortage of engineers qualified for that job is due to scarcity created by the US immigration policies. And then I'll ask you if you can't have your super high salary without exploiting the current system, your salary shouldn't exist.
Again, I'm not saying what they are doing is right or ethical or desirable. Just challenging the different point of views.
If you can't sustain your business without illegal (or in this case legal, but certainly exploiting loopholes which shouldn't exist) hiring/salary practices then why should your business be allowed to exist. This type of thing only hurts workers.