You're responding to someone who has taken a pretty strong position and backed it up with reason and anecdote. Don't answer it by telling the person who made the argument that they should feel guilty for making the argument. That's why everybody is stupid now.

Just tell them why they're wrong, point by point. Point out implicit premises that don't hold up. Do anything else other than try to convince the other person to stop speaking. People don't shut up because you tell them to, you have to make them shut up. That is a slippery slope.