My sole reason for wanting to try rhubarb pie is because of people who've had rhubarb saying how sour it is. I fucking love sour stuff, and celery. So hells yeah I want some rhubarb. I never see it around here though 😬
Its the leaves that have a lot of oxalic acid, the stems are edible raw, just utterly unpalateable. Although if you have a miracle berry first it is apparently delicious - https://youtu.be/hgvRoCY0hNA?t=10m26s
You mentioning eating the stems raw made me think of it and instantly increased my saliva production. It's not easily palatable, it's intense, you're right, but man is it good. I grew up on that stuff. Cracking that raw stem and munching it while doing gardening is a stimmy miracle