My dog responds to swear words by doing the kinds stuff you see emotional support dogs do in videos- press on your chest, give you kisses, nuzzle your face, etc.
Except she's small, blind, and a bit... intense, so she kinda launches into you if you're sitting, with some intense affection.
IDK why. I guess we don't swear very often, ao when we do, its special, and we swear with enough gusto for her to think we're very, very upset.