but I don't rule out every possible view of the divine, including for example a universal ethical theorem for sentient life which we have glimpsed fragments of but can't prove yet. Or, you know, something weird.

Neither do I, but I'm definitely an atheist. You can be unable to rule out a possibility without lending it any credence.

You can take it beyond the possibility of gods. Everything I think I know about logic and reasoning might be wrong. The universe might be held together by dream physics. I can't rule the possibility out, but I can dismiss it as remote to the point of irrelevance.