I think people cling to these theories in the hope they could explain every facet of human behavior. There's no Grand Unifying Theory of Relationships, period.

Certain people may act a certain way, but if you're choosing a mate, you don't want just anybody. Life isn't a popularity contest; you're not trying to capture the imagination of a random person. People mature at different rates, and have different value systems. These forces check our base impulses, and shape us into someone who is more than just the product of our own petty desires.

Worse, reductionism often carries with it an implicit acquiescence to terrible behavior.