It has nothing to do with race. You simply can't import the entire third world into the first world no matter how much the third world is suffering because it'll sink the ship, and they'll import themselves if allowed to because they're goddamn desperate. It's not a nice argument but it's valid.
Lets not kid ourselves. We're not what we were. Capable and ruthless. Look at these fuckers today. Neither. The average overfed American wouldn't last 2 days without a Slurpee and an electric armchair. Having to mow a lawn in the midday sun is a terrifying thought. Goddamn right you better slam the door closed, butterballs.
Though I’ve belted you and flayed you,
By the livin’ Gawd that made you,
You’re a better man than I am, Gunga Din.