And yes, that does make me wonder if I can trust that scientist's opinions even in their own field - especially when it comes to any controversial issue, any open question, anything that isn't already nailed down by massive evidence and social convention.

Not all scientists go around tallying up the expectations payed by their beliefs. If they have a freeloading belief they hadn't examined, one that doesn't affect their science, so what of it?

There's something fundamentally different between a gambling economist and a theist scientist: the thinking required for economics constantly forces you to acknowledge that gambling is dumb (although...). The thinking required for most sciences barely ever runs into the problem of God / spirit world / other wacky nonsense.

Most scientific reasoning treats God as a non-agent while never actually claiming atheism. A scientist who's never evicted a freeloading belief isn't necessarily a bad scientist. Theism is a warning flag only when it causes real-life expectations.