ME: I agree with your implied thesis that if there is infinite regression then the universe is fundamentally an irrational place. This, in fact, is what all theistic apologists have argued, from Aristotle to Leibniz to Kirpke: it's not impossible that there is no God, only that the universe would be senseless and irrational if God really wasn't there.
ATHEIST: There is a certain appeal of a god who exists to maintain order and stop the world from falling into chaos.
ME: You are completely misrepresenting what I said. I did not say that if there was no God that the universe would fall into chaos. What I am saying that if we've gotten to the point where you have a dilemma such that you have to admit that God exists or concede that infinite regression is possible, it is clear that you have to abandon all traditional conceptions of rationality to affirm atheism. Rationality has nothing to do with the maintenance of the universe. It has to do with how deal with the "justified" part of the definition of knowledge as "justified true belief." I cannot believe that you are so careless with your reasoning that you can just freely derive "Oh, Tom thinks that God is needed to maintain the universe" from "if there is no God then the universe is an irrational place."
He had no further comment after that.