It's not a subhuman trait on Chad, ethnic or not.
Curly hair is not going to make or break you. On Europeans and Asians it looks off, but true curly hair is extremely rare on whites and asians with no black, arab or jewish ancestors. I'm aware that some jews have curly hair, but unattractive jews are unattractive for different reasons and besides the kind of curly hair whites and jews have is different from African hair.
On blacks and most arabs curly hair is expected. It's just a part of being ethnic. It's like saying small monolid eyes are a subhuman trait, but it's just how asians are. You can be Chang and have monolid eyes.
I think no single feature is subhuman. Small asian eyes aren't subhuman, big black lips or very dark skin aren't subhuman and so on.