Is 'scientism' an anti-concept?

In discussions about philosophy and social science, the pejorative label of "scientism" often arises. It seems to have two definitions. The first is "the improper application of scientific-sounding jargon to rationalize unscientific assertions." The second definition is: "the application of any scientific discoveries to the discipline of studying human behavior." Many leftwing and rightwing activists say that those two definitions are the same -- meaning that any attempt to apply scientific discoveries to understanding human behavior is invalid, rationalistic scientism. They cite the eugenics movement as proof of this, and say that anyone who tries to apply scientific discoveries to understanding human behavior is as guilty of Scientism as were the eugenicists. I do think that some people cite neuroscience to foist irrational conclusions, such as saying that brain scans prove that non-leftwing people are more paranoid and hysterical than are leftwing people. But I think there are cases where applying scientific discoveries to studying human nature can be valid. Am I right to think that the pejorative label of "scientism" is a problematic "package deal"?