The junk science from social sciences is a combination of students/researchers who both lack the ability to read critically and are given work that requires it fundamentally. Any real critical sociologist is going to be far more scientific than most scientists when it comes to their analysis since they have both the rigour of their method and the eye of self-reflexive objectivity, but you don't always get those people. Mostly not, most academics are just fairly mediocre people who were smart enough to get through their classes, kissed enough ass, are seemingly competent and lucky to land a good position.