If someone denies a reality just to satisfy their own versions of truth, ego or fears, I’d just say say it once and move on. There is really NO need to explain and justify everything to everyone. It’s not our jobs to teach others to be more human and less stupid :-) As a stutterer myself, I just don’t care what others think - positive or negative. It’s like I don’t care if you think my hair is good looking or not. It’s amazing how much less I now stutter since I frankly don’t care what others think of it or me.