In 1981, U of I Professor Goodwin made the observation that Usenet discussions gravitate downhill.
He postulated that as the length of a discussion thread grows, the probability approaches one (1) that one participant will introduce the terms "Hitler" or "Nazi
The custom has evolved that the first party to utter "Hitler" or "Nazi" has lost the discussion, and the thread terminates.
Goodwin's Law has been invoked, guys. I'm out of this thread.