Sincere question -- what if he felt that it wasn't offensive enough to have crossed her threshold and continued making similar jokes? Your assertion is that he would be in the wrong, but isn't that entirely subjective on the level of offensiveness of the joke?
What if the joke were "Why did the chicken cross the road? To get to the other side!" and she said that jokes about chickens made her uncomfortable. Is he obliged to stop telling dumb chicken jokes?
What if the joke were "Why did the chicken cross the road? To get to the other side!" and she said that jokes about chickens made her uncomfortable. Is he obliged to stop telling dumb chicken jokes?