I'm not offended by the use of the word 'fuck.' I'm offended by the idea that throwing a tantrum is a reasonable or credible way to open a conversation. It's one thing to get passionate if the other party is being pointlessly confrontational or dismissive of genuine concerns. It might even be appropriate. It's quite another for someone to lead off with a shouty denunciation as if that person's opinion is the only one that matters and has no need of explanation.

Step back from the swearing and look at the context in which it cropped up. When an unfamiliar someone's entry to a conversation consists of blowing his/her top, it's usually because they're drunk or crazy. As William Burroughs used to say, 'I am not paid to listen to this drivel.'