Addicts love to go for shock value/attention. I have learned that just because someone adds "just kidding" at the end doesn't make it less hurtful, less truthful, or socially okay.
I feel like society is so quick to say whatever comes to their mind for whatever twisted reason they decide to say it and personally I am trying to make sure I am not one of those people and to surround myself by people who don't behave that way.
Great job not giving a reaction however, I'm not sure I would have been able to.