Why is it bad when a black man dates a white woman, but its okay when its another race? And why is it okay when a black woman dates a white man?

I’m black, and I always hear people talking about “Oh, that boy’s with a white girl, he should be with his own kind because there aren’t enough good black guys” and stuff like that.

My dad’s having an affair with a lady who happens to be white… I feel like people wouldn’t scream as much if she was black, but then again, maybe they would.

Does this make sense? =/ I tried really hard to get this to make sense, and I’m just trying to get this to… work out in writing as it does in my head. But even then, it’s not really that clear.