Calling (the public celebration of) 'Christmas' 'irrational'

The irrational part is that it's not about anything at all except self-indulgence in self-destruction. The destructive part about Christmas is NOT a belief (valid or not) about some historical event that (is believed to have) occurred at a precise point in the material continuity of material unfolding, but the self-indulgence in self-destruction that is cloaked in what I'd term 'coercive frivolity' (everyone feels that we ought to participate in the self-indulgence and excess).

Some say, oh, it's a myth and we should "celebrate reason"... Does my work does NOT (in some sense) "celebrate reason"?

Celebrating reason is not bowing before the goddess Athena or Minerva - or even paying lipservice to some image (mental or graphic) of the human brain. It's USING our lives (including the neurological capacities) to their optimal extent and keeping our bodies and brains healthy and functional for as long as possible.

Bring on the cultural anthropologists... I do NOT want to get drunk or eat dead animals...