This guy was an unbelievable asshole to you and you didn't deserve it. I carry the "stutter id card" with me at all times. If anyone ever does this to you again, you can just show them this and shut them right up. I would aggressively hold it in their face until they read all of it. https://www.stutteringhelp.org/content/stuttering-foundation-launches-id-card-people-who-stutter-0