The revelation of this law seems to be a bit of a bullshit retcon, IMHO. Up until now, for the past 3 seasons and some change, there has never been any indication that there was an official rule for this. And again, Happy does not appear to be too "Lilly White", and they had several non-white Hispanics in the SOA club down along the border from a couple episodes ago. This really feels like a badly patched plot-canyon to give Sheriff Angry-Black-Man a convenient axe to grind with the Sons. I'll still watch it all to the end, but if that's all this is, I've definitely lost some respect for the writing staff on this one.