We all saw what happened to kuma. He was turned into a mindless android by the WG and vegapunk and lost all forms of consciousness according to the manga. Logically speaking, kuma should by now be but a machine of destruction working for the world government however there are indications that he is acting in what could be considered an unusual manner. For one thing, he went to the sunny when the strawhats were gone and met shakky but even then he did not actually harm anyone and the sunny seemed fine for the most part. Sentoumaru mentioned that kuma had also been acting weird. If kuma lost his consciousness and became a mindless android, then he should pretty much do the WG's bidding at all times. Then what exactly is going on? The one who developed the pacifista is vegapunk and most likely he is the only one that really understands what exactly happened with kuma. In that sense, the most logical explanation about kuma's strange behavior has to be related in some form to vegapunk. we know kuma was a shichibukai but at heart he always was a revolutionary. Given that, would it make sense for kuma to turn himself into a powerful and mindless killing machine for the WG? Not really, whatever he did should by all intents and purposes serve some sort of greater good for the revolutionaries. That said, the only way for kuma's will to live under those circumstances is that vegapunk did something and was working with kuma all along.