User blog comment:Pacifista15/PX-Franky/@comment-4493594-20111122230209/@comment-3119203-20111123011131

They wanted to

1. Take away a Revolutionary commander.

2. Gain the power of the Nikyu Nikyu no Mi

3. Have a powerful subordinate. A regular pacifista wouldnt have the DF power or the fear from pirates that Kuma has.