I am in the exact same situation, I joined my friend's realm, who as far as I can tell does not have on any type of chat filter, and after cursing a couple times, which would have normally had no consequences, I was also banned for saying anything. Any message I put has the same message following it saying "The server has hidden your message for some players." This system needs very urgently to be addressed to at least like op said add a way for the actual server owners to see and change rules like these, or at the very, very least give us a timer or warning.
I am in the exact same situation, I joined my friend's realm, who as far as I can tell does not have on any type of chat filter, and after cursing a couple times, which would have normally had no consequences, I was also banned for saying anything. Any message I put has the same message following it saying "The server has hidden your message for some players." This system needs very urgently to be addressed to at least like op said add a way for the actual server owners to see and change rules like these, or at the very, very least give us a timer or warning.