The alternative is not that they be first class citizens, it's that they're not citizens (or legal residents) at all. They also wouldn't be desperately poor if they were legal residents.

For the record I, like most immigrants, am a "second-class citizen" who can't vote and would be deported if I committed a crime. I would prefer to be a US citizen, but since that's not an option right now I prefer being in the US legally with citizenship than being in my home country.