The idea that articles like this are science is a popular misunderstanding of science. The article is not a scientific work. It's a pop science piece where an individual scientist promotes her personal philosophies on love to a public audience. Her beliefs may integrate individual scientific facts but that does not make them scientific in themselves.
> Why are some romantic experiences (e.g. an unreasonable crush on a specific person that fades over time) so common in the general population, and why do these experiences happen and play out in these common ways?
Let's say you're feeling anxious before an important exam. Someone notices your anxiety and asks you why you're feeling that way. So you provide a detailed explanation of the neurochemical signalling cascade involved in an acute anxiety response and say that is why you are feeling anxious. Does this answer the question? In a very literal way it does. But it's a useless and incomplete answer. "I'm feeling anxious because I have an important exam coming up" is in many senses more useful and accurate.
Our biology is shaped and acted on by our environment which includes many psychosocial factors. Culture and individual experience are biopsychosocial. Biology is to human behavior what electromagnetism is to computing. You can't build an understanding by considering only the lowest level details.