I would argue that the person is at fault. Unless you are suggesting one does not have a choice whether to laugh or not.
If that were true, then all comedians would either be funny, or not funny, for all people. That is simply not the case.
I choose not to be offended by anything what soever. Humor on the other hand is a lot harder to deal with.
Almost everything that gets a laugh in a comedy show isn’t funny because it’s clever. What happens is the comedian says something “obvious”. They say something that you were kinda already thinking - even if you weren’t consciously aware of it. We laugh because we’re acknowledged and feel seen for what we were already thinking, and when lots of people laugh it feels good because we feel connected to the group. Our laughter is a release of tension connected to feeling part of the group.
If you don’t believe me, do the experiment for yourself. Watch a comedy show. When people laugh, ask yourself why they laughed then.
My favorite example is this clip of Billy Connolly from back when he would play the banjo on stage. Just as he goes to play the first note, the string on his banjo snaps. There’s this awkward pause, and tension in the audience. Then he looks up at the crowd and says “Well that’s just gone and F-ed it, hasn’t it?” And everyone laughs. My take is this: We were all holding tension. He said the obvious thing. We laugh because suddenly everyone realises we aren’t alone in our tension - suddenly we’re all (including the comedian) in this experience together.
“Offensive” humour is even more subversive than people think because it makes it common knowledge that we were all thinking some thought. It’s an opportunity to collectively acknowledge of our humanity. And that’s something some people (perversely) want us to deny.
It's not that everyone in the audience knew exactly what the comedian was going to say, it's that the comedian made them think something and then surprised them with something funny or offensive that's completely different.