As far as I'm concerned the Blood member was a connection of Ralph's son Joseph, not Ralph himself. Edwin Spears was to hand them customers, then how is he on the same level as them? He's simply doing the work for them. This type of affiliation between streetgangs and organized crime has been around for ages, its nothing new. Who do you think the Italians sell dope to? Only whites? Black/Hispanic street gangs are loyal customers.

And as Peter_Clemenza said, the mafia will deal with anyone making them money.