you are either willfully ignoring the fact that you are arguing about restricting the breeding of designated "inferior" immigrants based on their mental capacity (potential for success) as a proxy for describing yourself as "totally not racist and not eugenics" in any way, or simply don't understand the simplistic veneer covering your blatant support for eugenics. (you simply believe that arguing "capacity for success" instead of "race" is inherently different when it comes to eugenics...it isn't.)
You're pretty much picking some good blurbs to argue for what [DHT]Osiris has been saying, but you still don't get it. In the early days, classifying and restricting by race was simply an effective and well, the only tangible way to identify the "lessers." The only argument for eugenics has only ever been control for and select the most desirable traits of x population. That's it. It can't be more simpler than that. The eugenics policy that you have pointed out, in the past, is no different: pick those individuals that are best capable in our society, that have none of the "supposed negative qualities." Doing this by simply calling them jews or Irish really is no different than the very same end goal that you propose...but it is actually feasible, in a twisted way.
How do you even propose to select "the good and the smart!" immigrants out of those pool of outcasts? How are you going to screen them for potential economic value? This is more complicated than you are willing to admit, I imagine. It also rejects that "America story" that many seem to get a hard-on for: poor, downtrodden immigrant settles, makes simple life for family, where children and grandchildren thrive and, eventually, can become titans of industry.
Granted, that is rare to non-existent these days, but it certainly can't ever happen through an arbitrary screening process.
How do we determine that an "Elon Mush" (whoever that is) is actually going to be as successful as their credentials, and not just some lazy bum that only looks good on paper...or is simply a phenom in a land with access to nothing, but actually little to no potential in a land of equal competition?