They just bury the evidence when they get backed into a corner - happens more and more frequently.
If the moderators just wanted to stop a (supposed) flame war, they could just lock the thread. That would leave all the good, friendly, pleasant posts available for future reference.
Of course, it would also expose the looneys as the fools they are when they try to rewrite history and anyone could verify who did, and did not, start, or engage in, any supposed "flame war".
That's why they have to erase the evidence of their past perfidy. I guess we have no choice but to live with that for the moment.