Judging from your comment, it doesn't seem like you read the article or at least most of it. Either way, your criticisms aren't so relevant to the arguments I make.
Yes, when theists make empirical claims, those claims will be properly subject to rational (scientific or philosophical) evaluation.
But what about their nonempirical claims, such as the one I actually talk about in the article, namely the claim that God exists, that a supernatural being created all of nature? Science doesn't address metaphysical or normative issues.
Indeed, most scientists or atheists who are guilty of scientism don't consciously realize or admit to it. "Scientism" is a pejorative term, and as I say in the article, scientism isn't a belief or a theory as much as it's an attitude, specifically a prejudice arising from science's prestige. The prejudice is that nonempirical beliefs aren't worth talking about or that the nonscientific parts of our worldviews are empty, trivial, or bogus.
If you define "knowledge" as rationally justified, true belief, then there's no religious knowledge about supernatural matters (unless you count the mystical experience of peak states of consciousness or of the world's oneness).
I take a more pragmatic view of knowledge, since the correspondence theory of truth is based on magical thinking. In that wider sense, religion can count as knowledge because of its social function. Science enables us to control the natural environment, and religion enables us to control populations of average people.
Incidentally, your condescension flows only from your ignorance about me. I did my Ph.D. in philosophy under a philosopher who did his under Dennett. It's best to avoid personal attacks, especially when you're speaking from ignorance.