> Also, if we discriminate on merit, then racism is also fine?

They can "limit" based on skills, they can "limit" based on country of origin with the main difference being not using the hot-button word "discrimination" to, err...discriminate between the two while implying some sinister race-based system of visa allocation.

> Maybe we should only discriminate on an individual level and with the attributes that individual has under his control.

They you'd be "discriminating" against people who can't afford advanced degrees from prominent schools who just want to work hard so their children can have a better life like the countless number of first-generation citizens I've met over the years. This is where I'd put a "why you hate poor people?" to make my point but I know that's not what you're arguing.

Of course you think that it's fair to discriminate based on skills, because it benefits you. That's not how the rules are though. If Green Cards were based on the queue length, then Indians would starve out every other country, and that's not how the US has decided to approach immigration. There is a set limit based on country. Just because 1 country has more applicants doesn't mean there's discrimination. Having a set limit per country ensures that everyone globally gets a fairer shot, just because you're not getting what you want doesn't mean there's discrimination. Letting you in would be discriminating against someone else in another country.

The idea is to give people from all over the world an equal shot, not to just skew in favor of one or two high population demographics. You can call that discrimination if you like, but in the “discriminating tastes” sense not the KKK sense. The alternative is to discriminate (in the negative sense) against people who don’t come from a population in the billions.