Sounds like urban myth. It's more likely that hoods became popular for the same reason that KKK hoods were popular: to conceal your identity from casual observation.
A guy wearing a hoodie is going to have his face being less visible to security cameras, and is less likely to be recognized at a distance by rival thugs.
I worked with guys that were Black Klan in the late 70’s.
As far as I know both got out of it when they realized the white man wasn't the cause of all the black problems.