Yes, they do, as I described in my earlier post. They are as surely members of the religion of Scientism as a man who stands in the town square and preaches salvation through Jesus Christ alone is surely a Christian...or pretending to be one so hard that he would be a fool to object if someone called him a Christian.
If I did everything I do now, and someone described me as a Christian, I would have no grounds to object, even if I had never told them I was a Christian. Though I'm far from perfect, I have gone out of my way to practice Christian tenets.
As for the "abuse" of making it a religion, every religion believes it has saving knowledge for humanity. So do these folks...and they believe their's is the one true path. Sounds like a religion to me.
There is no reference to anyone professing a belief in "Scientism". Are you professing it for them, or are you submitting that Colson has and that he has the authority to do so?