Even if we did have only Christians in our midst, if we expelled every non-Christian from the United States of America, whose Christianity would we teach in the schools? Would it be James Dobson's or Al Sharpton's?Obviously this was just a way of illustrating the fact that even Christians often disagree with each other, but Dobson decided it was insulting because it implied that he's on the right and Sharpton is on the left. And anyway, it's offensive to even mention him in the same breath as Sharpton. I guess it doesn't take much to get under Dobson's skin these days.
(The rest is about whether the Old Testament really applies to Christians etc. etc. Feel free to listen to the whole thing if you have a greater tolerance for this kind of discussion than I do.)