Why is Badzen unfriendly to Camus?

Because Badzen thinks Camus Sama is always deceiving himself.

For example, when Camu gets a few diamonds, he will secretly make a diamond shovel for the black cat and call Milo as soon as he finds something good. In short, Kamusama is good to everyone except himself in Badzen's eyes.

Camus Sama will take care of those who are weak or younger than himself after all, which is perfectly reflected in Milo and the black cat.