Just because it didn't happen, doesn't mean the possibility of it happening is not there. What, Dragon is just supposed to believe that there is no way the WG can retrieve information from their cybernetic experiment? Come on now....
And I find it funny nobody said shit when Dragon basically told Ivankov to kick rocks for trying to pry into his personal life, but now it's a problem when he does the same with Kuma.
The reason why it is more to the extreme with Kuma, is because again, the risk is there for the World Government to be able to get real information from him, that can be detrimental to Dragon's origin, which could cripple the Revolutionary Army.