Social sciences like psychology and sociology may not be able to draw affirmative concluisons about causation, at least no more than the natural sciences, however accumulated correlation can permit informed decision making or speculations which can be very useful, at the very least it makes for interesting reading. Not that novels or literary sources dont have as much value sometimes.
If you seriously question the objectivity and use of disciplines like sociology and psychology you then have to seriously question the sorts of pop sociology or folk psychology on which most people base their judgements and from which unconsciously social norms rise and fall. It makes the culture wars appear like a lot more than simply a contrivance of stuffy conservatives or alarmist politicians.
I find it very interesting what is and isnt considered credible in the disciplines of sociology and psychology, what those accreditation and doubts say themselves. What is rubbished in straight macro or micro sociology will be considered valid once marketing or management professionals are able to use it to make money. I remember a great politics lecturer at one of the universities I attendend contrasting the content in economic texts about incentives and profit with what the top five management text books suggested about incentives, the whole comfy chair vs. bonuses discussion.