In reality that would be like Hibino is affected by a plague or is a spy from the enemy camp.
However nice he may truly be, how close he is, you can't forget how dangerous it is to be too trusty.
It's even worse than that. Hibino is perfectly fine and feels totally in control. But who knows if/when the beast powers take over and he becomes the worse Kaiju to date?

My guess the last eps for this cour will try to answer that and how the top kaiju extermination bataillion can accept a human/kaiju hybrid in their ranks.