I hate that feeling.. the knowledge that engaging in the discussion is going to be exhausting and the chance of making traction is slim, and the feeling that inaction is the only reasonable alternative. Allow me to suggest another alternative to actual discussion in situations like this: Tell the person to fuck off. I'm serious. It registers disagreement, and to any rational person the lack of interest in attempting…
I agree about the need to clearly register disagreement, but I'd opt for slightly less shock... I'd say, calmly and sternly "that is entirely inappropriate." I'd then call on others in the group to register their disagreement.
"What you just said disgusts me" seems more fitting. You're communicating how it is personally affecting you. That can't be argued.