Because it's a public server, which means Discord feel it reflects on them as a business to be hosting hostile communities. You can say whatever you want in a

Because it's a public server, which means Discord feel it reflects on them as a business to be hosting hostile communities. You can say whatever you want in a closed, private discord group. Discord isn't going to care if it's a server with a dozen users who are all close friends. It's when you go posting invite links everywhere and get a community in the thousands that Discord start taking an interest and enforcing their brand protection.