Does psychology diss-empower people?

I'm taking a psychology course for the first time. I'm wondering does psychology ever get annoying because it's like having someone tell you how you should be thinking? For example I red in a psychology textbook "men date women how are younger than them" and I found it kind of dumb because that's not true for me. Also it doesn't answer the question why. Does psychology answer the question 'why'? It seems to me that psychology has no system for coming up with mental disorders/illnesses and psychologist happ-hazardly make things disorders.