No, just no.
RoNi you are going extreme recently, a perm ban? Ofc i am not aware if warnings were given or not in game but a perm ban is too much for such a person. Karimoo is a really friendly guy, one of the only people that i think make JB fun and accepts everyone as a friend. I am sure Karimoo did not intend for such an event to occur, but their could be a background story to this too. As Karimoo said, he does not use the push to talk function, so it really is not as a bad of a thing, if he had the ability to quickly close his mic and stop it then maybe a warning would be good.
But TBH, we all swear. On TS3, Steam, In game, IRL. Ofc i do not know the amount of insulting and swearing emx said, but if no-one warned karimoo then i see no wrong doing. As a normal player and not an admin, Karimoo can choose what he wants to do, he is not an admin to represent Ambrosia and its rules, ofc he has to follow the rules but there are no specific rules saying he cannot keep a perm banned player secretly on the server.
However as i shall repeat, i have no idea if he was warned before the ban, if not, he should be unbanned.