The word “long” is where?
One assumes if a woman doesn't cut her hair, it will be pretty long. (And the verse I quoted indicates it is disgraceful for a woman to cut her hair.)
Truly, I'm being facetious here. I believe the intent of the passage is to teach women to avoid doing anything with apparel or hair that would appear to be disrespectful toward the Lord or immodest in any way.
After all, what does "covered" or "uncovered" mean anyway? I doubt the women in biblical times wore a little doily on their heads. Doing so would probably have been viewed as disrespectful and immodest. Such "decorations" would probably be viewed as something to be used by prostitutes.