Persons A are much easier to present to the general public as generating negative utility, and thus compromise the perceived value of a wrong worldview. This makes our job a lot easier when we expose what they are doing.

Also, they are probably far less dangerous when dealing with existential risks. Let's take something that seems common (in the US, at least), say, subscribing to a premillennial eschatology. If we put one of the two in charge of a superpower:

• Person B might be willing to start or escalate to a global nuclear war, because they are on the "Right Side", and Jesus will come down from the heavens to explicitly make sure they win.
• Person A will probably not.

Both are bad, but I'd clearly prefer more of Person A and less of Person B.