A version that's not even a little insulting might look something like "Not all simulations are ancestral."
There's a difference between “it is unreasonable to think X” and “not X”. (Let X equal “the sixteenth decimal digit of the fine structure constant is 3”, for example.)
(I'd use “There's no obvious good reason to think that all simulations are ancestral.”)
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Of course, for "every Monday", the last one should have been dated July 22-28. *cough*