I find the pains-taking, deliberate coiffure dreads on certain white folks a little annoying, too, but not so much as the overwhelming stench of patchouli those same people tend to be douse themselves with. Not trying to downplay your point, but white peoples' hair varies greatly in texture and can get matted into dreadlocks. You'll see it on crazy homeless folks who are not trying to look cool. White people with naturally curly hair can start dreadlocks in under a week just from not brushing their hair. And you don't need to be mixed race to do that. My cousin is an ethnically Scots and German, very white, freckled, curly ginger haired man. When allowed to grow long, his hair would puff out similar to an Afro, or more like a red clown wig. He let it go to dreads for a while in the seventies because he liked to go surfing all the time, and keeping long hair like his combed was impossible after all that salt water, wind, and sun bleaching.
