Are we to believe naively that these people are just bad?

I don't think Satan's direct action is needed to tempt shitbag people into public office. It's difficult for honest people to make it because they're honest and the system selects against that, and it's easy for psychopaths because the system selects for it.

Satan doesn't need to be piloting around assholes like shikigami, he's much more sophisticated than that. He made a machine to bring them right to his door on their own volition.

If you have a mouse problem, do you go around catching all the mice individually, or do you just set up some traps and let the mice come to you?