Holden did have some interest in religion but was turned off by hypocrisy and empty formalism. I think the point, though, is more that writers have to write their “Inferno” or “Purgatorio” before they can consider “Paradiso,” that is, they have to depict a godless world before they can move on to a religious vision. In Salinger’s case, though, that vision would be as much Hindu or Buddhist as Christian.
To the contrary, I’d say writers should start with truth in order to illustrate the absurdity of falsehood, rather than starting with falsehood in order to create the facade that they’re seeking truth.
And my gut tells me Salinger could have been a satanist.