I'm conflicted about my feelings about this, but that's exactly my intent when I speak like this to someone. It's the desire to make them feel small and communicate how little I have respect for them in that moment. I'm honestly not sure if that's healthy. If I was charged with defending the opposing view I'd argue that it's fighting bullying with bullying, or that maybe the ability and desire to make insensitive comments like that in the first place come from feeling small and I'm only fueling the fire. I'm really not sure. I just know that it's worked for me in the past, at least in the small... in situations where I've wanted to diffuse a situation and shut someone up who's expression was abusive. I'm not convinced there's not a better way, though. I just really hope the takeaway to this thread isn't that I think it's obviously perfectly righteous and productive to react like this, just that I think it's (at least occasionally in my experience) effective, and vastly preferable to doing nothing.