Char Auths are often of sensitive IC data, such as = I would like an auth for my rebel character to make a bomb/do general rebel stuff. Having them be private means that Loyalist players can't check Auths to see who is a rebel and metagame information. I imagine there's a similar logic for the loyalist side of things, Eg, an auth to start a specific loyalist project that they don't want rebels to metagame the knowledge of and sabotage (like how rebels like to do).