Just because you follow me, or if you see my posts on your Fediverse feed, doesn't mean you have permission to say rude or cruel things to me.
I know some friends do this as a way to express intimacy. I don't usually talk that way with friends, but I understand that some people do it.
But that intimacy is earned and negotiated. Just being on the same social web is not enough.
If the first time I interact with you, you insult or attack me, I'll block you. I can't tell you're "only joking".