This is not really related to gaming, but is something I've been contemplating lately.
Let's say that there is a statement X. You do not believe that X is true. You think it is wrong, that it does not describe the reality of the world.
There are other people out there who do believe in statement X. Who believe wholeheartedly, who believe that X describes a truth of the world. And because they believe in X, they act in a certain manner.
The issue is that because of the way they act, these people accomplish more than your group. They never prove X, and it is entirely probable that you are right about X. But still, in pursuit of X they do more, even make the world a better place, than your group does.
Should you join this other group, even if you don't believe in the fundamental principle which they do?
Perhaps believing X to be true might lead them down a wrong path someday in the future. But so far, other people believing in X has just resulted in outcomes which you like.