"Anything's real if people believe in it enough," is the simplest way to explain--everything, but especially his experience of the supernatural. Wendigo might not be as common as they were in the days of settlers and starvation, but they still happened, and it was easy to keep believing in something that killed friends or family, which kept the problem, well, alive.

Flippancy is his best defense: he can't pretend not to know what he knows, but he doesn't have to lend it any power. Especially in a place like this. "Tuesday is a social construct that dissolved months ago, but, sure."