If beauty is tightly associated with facial symmetry, then why doesn’t everyone have their hair part down the middle?

Edit: to clarify, I know that many short hair styles don’t have a part at all. Mostly talking about people with hair long enough to have one. I find it interesting that many studies conclude that beauty is tightly correlated with how symmetrical someone’s face is. However, many haircuts and hair styles are asymmetrical, including any style with the part off-center (very common for both male and female hair styles). Not just that, but we really like the way these haircuts and styles look too. It makes me wonder why one’s perception of beauty might not take into account the symmetry of one’s hair. I don’t have an opinion on what looks better, symmetrical vs not symmetrical as I think it depends on the person and what suits them. I am wondering if anyone else has thought about this.