My gut is telling me that a win against Nelson does nothing for his cred or putting anywhere near a title shot. A lose to Roy would severally hurt his cred. Also if he is French he might be worried about visa issues no sense taking a fight you might not be able to get into the US for. I know at best he is HW gate keeper but looking at it from his perspective.
people also have to realize that managers/teams have to agree to contracts before a fighter signs. Nelson is good....but fighting him would have done nothing for Kongos career currently