There's a similar bait and switch in the writings of Paul Tillich, who I otherwise admire. He defines God as one's ultimate concern, which I'm perfectly willing to get on board with, and says we shouldn't confuse faith (having an ultimate concern) with belief (maintaining a position about some state of the world). Again, no quarrel from me.
But then he says that to be an atheist is to have no ultimate concern. And I'm like, hold up, says who?
What Peterson and Tillich both refuse to do is to acknowledge that the VAST majority of self-described Christians would never recognize their existentialist concept of faith. The distinction between faith and belief has never occurred to them.
Atheists reject what Tillich calls "belief" in a god or gods. But they don't necessarily reject what he calls "faith" in some higher values like Truth or Justice.
If anything I think us atheists often have more faith that religious people.