The mass of people who provided popular, democratic support for visa restrictions were motivated by the nativist concern of protecting American workers from foreign competition. You can always attribute popular sentiment to mustache-twirling elites pulling the people's puppet strings, but there's no getting around the widespread, populist fear that American workers would lose their jobs to foreign, racial others who were inhumanly smart and/or inhumanly hard-working and/or willing to live in inhuman conditions.
Liberal economic elites would have preferred unrestricted, laissez-faire access to technically skilled immigrant labor rather than being forced to deal with the caps, lotteries, and bureaucracy associated with the H1B program.
> The mass of people who provided popular, democratic support for visa restrictions were motivated by the nativist concern of protecting American workers from foreign competition.
Why would they support H1-B then? It is literally increasing supply of workers who have less negotiating power than the “mass of people” I presume you are referring to. Surely they would be better off with immigrants whose legal status was not tied to employers.
A common refrain you will hear is "Americans don't want to do those jobs", but what that misses is if you gave a immigrant the same rights and opportunities as a citizen they won't want to do that job either (at the price and on the terms offered). Relatively open ended immigration programs with minimal restrictions are defensible, but this caste system is not.
> It is literally increasing supply of workers who have less negotiating power than the “mass of people”
It restricts the number of workers that are able to work in the U.S., and forces companies to jump through hoops to hire them. The idea was that companies would be forced to hire American workers whenever they were available, and only rely on foreign workers as a fallback. Obviously corporations were able to somewhat neuter the law so that it wasn't as much of an obstacle as it was sold as.
> less negotiating power
Protectionists were convinced that foreign workers would undercut them by working harder for less money in worse conditions; the idea of foreign workers actually helping improve working conditions would have sounded ridiculous (if not faintly sinister) to them.
> It restricts the number of workers that are able to work in the U.S., and forces companies to jump through hoops to hire them.
Restricting workers would be denying them entry into the country to work in the first place. And forcing companies to jump through hoops simply means instead of lower paying employers taking advantage of the visa, higher paying employers take advantage. Either way, there is going to be an increase in labor supply of people willing to work for lower wages (since they cannot shop for other employers), and that negatively effects all workers.
I think you're talking about the truth of the matter, but I'm talking about what motivated the creation of the program in the first place. Economic liberals wanted unrestricted access to labor regardless of borders, protectionists in the U.S. did not want to compete against labor from other countries, and the H1B visa program came out of that conflict.
Liberal economic elites would have preferred unrestricted, laissez-faire access to technically skilled immigrant labor rather than being forced to deal with the caps, lotteries, and bureaucracy associated with the H1B program.