Scientism is, as you say, “ about faith, belief and doctrine.” As such, it deserves its own ecumenical tag so that it can be free of the religious zealots who jump on it.
If scientism (however you might define that term) is a religion, then everything is.
***You’ll need to expand on your reasoning here because it doesn’t really make much sense. Science is not a religion, but putting your faith in science is a religion. It’s that faith element that is the point of departure between science and scientism.
That makes no sense to me. If a belief in science is a religion, then it means that there is no such thing as a scientific fact, only scientific doctrine or opinion.
2 + 2 = 4, not in any real sense, but only if you believe it and have faith in it? Then perhaps it's equally valid that 2 + 2 = 5, or at least that it's debatable. Maybe it depends where in the world you were raised and in what culture and religion.
What's more realistic is that good science takes religion out of the equation so that people of any religious background can indeed agree that 2 + 2 = 4.
The belief in that doesn't need any ecumenic protection. Perhaps what needed protection were the scientists who were presumed to be atheists because they reached different conclusions based on evidence presented outside of Sunday School class.
Simply because they reached a different conclusion does not mean that their conclusion had anything to do with religion. Science and religion are not the least bit in conflict unless someone wants to pretend that they are.