Tsun in the streets
I've seen them both used with referring to a person. "You are unorganized." and "You are disorganized." I think it has something to do the prefixes 'un' and "dis". Disorganized is usually used to refer to a person. While unorganized is usually used to describe something that wasn't organized in the first place. A state of "unorganization". Like a box of Legos or something.