Curate, connect, and discover
Other similar things people say are:
"Oh, I was just curious."
"I was just asking a question!"
"Apparently you can't take criticism."
"If you can't take a little criticism, you shouldn't blah blah..."
"I'm just sayin'!"
"You need to touch grass."
"You take everything too seriously."
It's all the same redirection trick.
Complicating matters is the fact that not everyone who redirects this way is consciously aware of what they're doing and may not even have genuine malicious intent. People don't want to admit to any bad qualities... some people redirect like this so they don't have to admit to themselves that they were thoughtless or malicious.
That doesn't justify their behavior, however. It just makes it harder to correct.
You're not "too sensitive" for getting upset when someone purposely upsets you. It's not "just a joke". They know what they're doing. They're just hiding their bullying behind the label of joking so they can play innocent.