Internet Stalker
They say that the best way to confront someone who said something uncomfortable (racist, sexist, whatever-ist), ask them politely to repeat themselves. When they do, they’ll hopefully hear what it is they said and stop their bigotry for at least the time being. Give it a try, you’d be amazed by how some people don’t know how hurtful their words are until they hear it a second time.
This woman couldn’t do that to this guy since they were communicating via text message, but she could respond with a meme that showed him exactly how annoying he was. That ought to shut him the heck up.