It is a distortion of the critique of scientism to muddle it with theological faithism. Faith is a religious stance, but one that is not an alternate form of knowledge. On the contrary it tries to create a venue whey the path to knowledge (of god) has failed.
Atheists have a pronounced leaning toward scientism, which is the belief that science is the only reliable source of truth. It’s entirely understandable, then, that belief in God might look to them like wishful thinking – as though people of faith have let their hearts overpower their heads. . . . We fully acknowledge that emotion can get in the way of clear thinking, but since we see this as a very general condition of humanity, we would never offer it as a particular weakness of atheism, the way so many atheists offer it as a particular weakness of theism. (P. 7)
The issue of scientism is better taken in a Kantian vein where the ‘critique of metaphysics’ is applied to both science and religion. There the question of ‘god’ is not a standard issue of knowledge.