If it was “just a joke”, then there's no reason for you to be upset that people didn't find it funny. You'd just accept that the material fell flat, note it for future reference, and move on.

But, if it angers or frustrates you that people didn't find it funny, or tell you that it was offensice, then it wasn't “just a joke” to you. It was a belief that you shared in a joking manner and you're taking the rejection of it as a rejection of part of you.