My oldest DD had both IUDs and irritation that hurts like hell (but no IUD) from bubble baths, or even from a bit too much soap not thoroughly rinsed. So yeah, no bubble baths in this house. I need to take the shower head and hose her down after every bath.
They are, but apparently (?) sitting in the bubble bath (which is a potential irritant) can lead to itching, etc. There's even a term for it: bubble bath cystitis. I had tons of UTIs as a kid, so maybe that's why I've heard of it?
I was brainwashed too. We've used certain bubble-like products that even say (in super fine print) that it might cause vaginal irritation. We haven't used full-on bubble bath with her yet.