Religion makes a lot of leftists uncomfortable, especially those involving patriarchal, anthropomorphic gods with a specific idea of how people should live and the reputation for taking a very personal interest in whether people live that way or not.

I think it goes back to the 60s and parental authority issues.

Religions involving crystals, vague nature forces, benevolent aliens, or gods that have no rigid rules or real interest in you, seem to be okay.

Patriarchal, anthropomorphic gods of religions that are intensely anti-Western and anti-American get a special pass from the Left, if a grudging one.