Having swearing as a personal signature is like having a tattoo. It doesn't make you any "cooler", and everyone does it so it's not much of a signature.
It's not that it's offensive, it just says you are unable to convey the strength of your argument without the vulgarities. You lose critical (logical) thinkers when you resort to crass language; primarily because it says your argument relies on emotion, not logic.
In a discipline such as computer science, appeals to emotion are inherently untrustworthy and distracting. A reader shouldn't have to shift through pandering rhetoric to find the kernel of a supportable argument.
It's not that it's offensive, it just says you are unable to convey the strength of your argument without the vulgarities. You lose critical (logical) thinkers when you resort to crass language; primarily because it says your argument relies on emotion, not logic.