No, I saw their actions and judged them based on the definition of Scientism. Sure, I used the example of the Christian religion as a comparison, but I could have used another religion, or a non-religious activity. In fact, I will now do so:
A man buys a bicycle, bicycle shorts and a bike helmet, rides his bike to and from work each day, subscribes to Biking magazine and enters several local bike races. By the measure I'm using he is a bicyclist. By the measure you're using, he has to stand up in a public forum and say "I, John Doe, am a bicylist" and if he hasn't, anyone who thinks he is a bicyclist is way out of line.
What't the practical difference between "scientism" and "heretics"?
Well, I'm sorry to tell you this, but it appears you don't even know the terms you're dealing with, because a person is only a heretic if they reject doctrines held by their own religion, not those of other religions. So, if I were to dispute the Resurrection, I'd be a heretic, but a Muslim who did so wouldn't be.
However, if we're going to discuss heathens, from the Christian point of view a Wiccan, a Buddhist and a guy who wants to wipe out religion so we can all bask in science's warm glowing warming glow would all be heathens. But from any point of view the last guy on that list would be a member of the scientism cult.
I've noticed you have a very convenient habit of ignoring questions asked of you and responding with questions of your own. I've answered every one of your questions, and I expect the same courtesy. You can start with this one:
Let's put aside the idea of religion. Do you really have any doubt that these particular individuals ascribe to the idea that "natural science has authority over all other interpretations of life, such as philosophical, religious, mythical, spiritual, or humanistic explanations?"
If I'm expected to make a well considered determination about that, it would help greatly to know exactly who these "particular individuals" are.