Do you, then, never make a mistake and make a joke that, though innocent to you, may annoy or hurt someone else? Because if I made a joke, and got the "interesting assumption" comment, my thought would be, "Oh, I put a foot wrong there. Better apologize, and move on." Not "Wow, that person HATES me, and is probably crazy. I'd better never speak to her again."
Even with the best of intentions, people make mistakes in humour*, but getting offended because people react to those mistakes in a mildly negative way strikes me as blaming the victim.
*For example, if your friend repeatedly asks strangers for designer drugs, they may one day ask a recovering addict, or someone who recently lost a friend to an overdose, or someone who is on probation for a drug offence and hopes no one knows. That's part of the risk with making those sorts of jokes with people you don't know. You assume that if the person asked says, quietly, "that's an interesting assumption," that the rudeness is on them, and I do not agree with that.