I hate feeling like a reddit atheist, but it feels really hard to imagine any organized religion not being a ticking time bomb in a communist society. You can bend most/all religions to fit communism in the same way you can bend them to fit capitalism and social conservatism, by ignoring the parts you don't like. However to me it seems like an organized religion is going to breed dogma and an in-group which is going to breed out group and discrimination. I'm pretty sure it's hard for me to look past my bias though, as my experiences with religions is mostly them wanting me dead.