From time to time in discussions, people will use a phrase like the one above. What it means, of course, is that the recipient is an idiot who doesn’t understand what’s going on. The statement means “I cannot refute your foolish and unrealistic argument but I don’t intend to change my mind.”
Still, it’s not quite as bad as “In the real world …”. You have to admit that.
“What color is the sky on your planet?” is right up there too.
If you ever catch me using any of these phrases, call me on it. I’m in the book. The Mars book.