Yes, that's true. The same is true of the word 'wrong'. But that perjorative usage doesn't discredit the concept of scientism any more than it discredits the idea of right and wrong.
Those who employ the concept of 'scientism' aren't typically doing so to attack science per se. They use it to criticise what they perceive as scientific overreach and authoritarian uses of science.
Have you ever seen anyone claiming that what they are proposing is wrong, but continuing to advocate for it anyway? Isn't 'wrong' an idea that's more typically wielded by critics of the proposed idea or action? That doesn't in and of itself discredit the idea that some beliefs and actions are indeed wrong.
I think I would expect someone to use the word 'wrong' in reference to a specific misuse of science. To my mind, creating the word 'scientism' implies a fatal flaw in the way science is practiced in general.
I often hear this nebulous criticism of scientific overreach and authoritarian use of science. I would love to have concrete examples of both categories to evaluate such claims.
You seem to me to be inching dangerously close to the idea that science shoud be immune from criticism and that those who speak in the name of science must automatically be believed as society's ultimate authorities in all spheres of human life. That may or may not be what you meant to imply, but I find the idea to be quite authoritarian.
I find the suggestion that I am implying science should be immune from criticism quite amusing. The whole idea of science is to apply reasoned and rational skepticism to everything we think we know, that nothing is exempt from reevaluation. That is the whole point. We human observers of reality are flawed and fallible creatures. We need some method of quality control to mitigate our fallibility. Science, the principles and standards of science, are required in knowledge pursuits that address what is real and existent. It does not cure human fallibility, it only mitigates it, and science done properly understands and embraces that fact.
If there is a better method outside of the way Science is currently conducted that would better achieve the goal of discerning what is real and existent, then Science would love to hear it, for that would be 'doing science'.
When you reference 'all spheres of human life', it would be nice to know what you mean by that. What sphere of human life to you consider to be negatively impacted by Science?