Note that at the very beginning, the guy running the seminar says "we've spoken with the employee, we've spoken with the immigration specialist" -- in other words, they already know exactly whom they want to hire. They're trying very hard to avoid hiring an American.
This is talking about the tech field, and given that we in the tech field do pretty well, I'd be perfectly happy to let more folks immigrate and participate in the field... But, this same attitude is at work at the low end of the labor market, where it's a matter of whether we're going to let our countrymen live in abject poverty... We do not need a "guestworker" program, which makes people dependent on their employers to stay here. If people are good enough to come for a particular job, then they're good enough to come, period, and shouldn't be tied to that job. They deserve the same bargaining leverage a native would have, and should definitely be on a "path to citizenship" like our Ellis-Island ancestors, if they want it; not a path that sends them home in a few years.