I've no particular love for "Captain Everything", but Superman was a Moses allegory written by two Jewish guys about a man who has no stakes in his new world other than the loving people who took him in and his desire to do good for all, even the haters. It's about as pro immigration as you can be.

Granted the line was from a complete cretin in original delivery.

I would have gone with "somebody peed in his mother", one of my favorite lines from Amélie.