Data point: I picked this option, because of a grab-bag of vaguely related positions in my head that make me feel dissatisfied with the flat "atheist" option, including:

• I enjoy and endorse rituals such as the Solstice celebration, as opposed to the set here who are triggered by them (ETA: not in any way claiming they are wrong to be so triggered, or don't have reasons)
• I find the Virtues, and other parts of the Sequences with similar styling, to be deeply moving and uplifting, and consider this element of our house style to be a strength rather than a liability
• We worry too damn much about the c-word, in a pointless attempt to appease the humourless, and we've compromised too much of our aesthetic identity doing it
• Scott's Moloch isn't actually the Devil, but maybe acting as if is a good strategy for recruiting all parts of our minds to the fight. Ditto for Elua
• After some experimentation, I think I understand better what the mindstate associated with "worshiping" actually feels like (really damn good) and suspect that the emotional benefits are totally available even if you know the targeted god doesn't exist

(I actually wish it was reversed to "religious but not spiritual", because "spiritual" feels more like the "supernatural/irreducibly mental" word, whereas "religious" feels more of a piece with perfectly sensible things like not breaking my word even to save humanity. But that's just me.)

I have no idea whether this is remotely related to postrationalism; if anyone actually knows what postrationalism is, please write a FAQ. I do miss Newsome though; he wrote my favourite ever LW sentence.