Sometimes, it is best to recognize the futility of engaging.
Agree. In two absolutely futile cases I no longer engage, at all, ever.
In the present case, however, a short, simple statement was made. It should have been very easy for that statement to be backed up and validated. But it wasn’t; the back-up evidence has not been provided and probably never will be.
It’s typically this way with a particular kind of belief system. Statements are routinely made that cannot be substantiated. That’s just the way it is, because the system itself rests predominantly on belief, as opposed to resting on facts, logic and evidence.