Meh I've always interpreted the dreads to be something along the lines of hair... very
alien hair but hair. From what we see they serve no purpose in yet have so many similar properties to that of human hair. Growing along similar parts of their bodies, varying in length and graying with age (of course skin also lightens with age too). Stan did refer to the dreads as hair. Now the new movie is implying other things. Casey didn't exactly get to study the locks so her guess, frankly, is as good as any of ours. They don't exactly fit the mold for any sensory organs of any creature on earth, to my knowledge anyway. If it does have a purpose, perhaps it's some type of meaty tendril that helps regulate body temperature.
Regardless, I don't see the issue with other creatures, that come from their planet, also developing them.
On a side note, I found the NECA Fugitive figure in Target and had to get him.