It's 2020 and these statements are kind of necessary everywhere. In my experience with the scream jams, I haven't seen the hosts remove anything other than spam submissions. No game has been too scary or dark (and there has been some REALLY dark stuff).
Your characters are allowed to be bigots and racist and sexist and violent and terrifying and inhumane etc. Your game's existence should not be.
I think what the hosts (for the Scream jams) are saying is your game should not be morally reprehensible nor encourage and idealize such behavior.
For the record I'm not a host, just a scream jammer with my own interpretations.