I'm sure EB had his tongue firmly placed in his cheek when he wrote that one - but it's true, he'd never get away with performing it in case someone took it seriously.
I agree with those who talk about the advantages of a multicultural society and that many immigrants are taking up jobs few of us would touch (to be fair, though, there's also the argument that it helps keep wages low).
Personally, I'd welcome as many as want to come here. In Scotland we have a dwindling population and bags of room. I have four kids and an English wife, so I reckon I've done my share :) - so let 'em come! Even the weather's better than it is down south these days :)