Speaking as a long time asshole?
Acknowledging that you are an asshole in no way mitigates the fact that you are, in truth, an asshole.
Speaking as a long time human:
Never assume anyone else's experience.
It's not "just the internet".
You're not "just kidding"
You're not "Keepin' It Real(TM)"
It's not your job to "Toughen Them Up"
They do not need to learn it sometime.
That's all just bully speak and rationalization.
There's a way to be a person about a thing. Do it.
Civility isn't about the PCing of America. It's not about being a candy-ass, it's about remembering before you let your bile escape that the person on the other end of the send button is a person. Nothing more.