Dealing with no permission asked public outing by flaming gay strangers.

I was walking into a convenient store today and when I got out a group of people outside were laughing at me for some reason, I knew none of them, none, and as I walked away, someone shouted "SEE YOU IN GRINDR!!!".I know this might sound strange but I feel...in a way...violated.This nobody flaming gay guy outed me right out in public.Who do he think he is to take this right away from me and just throw it out there, I don't even know that guy.Have you been outed without your permission in public before and how do you deal with the mental trauma ?