I think you might be reading into my words a bit too far. The Mafia is not a legal employer. Requiring someone to have a legal employer in order to buy a legal weapon makes sense. (Perhaps. Maybe it makes sense for them not to have an illegal employer.) At any rate the Mafia do not generally buy legal weapons. As for not letting somebody buy me a drink, that's not exactly organizational discrimination - it's more like personal discrimination - but not letting a certain class of individuals enter a bar based on their legal employment is. Personal discrimination is a lot murkier, and everyone does it to some degree.
I know that I didn't make the distinction between legal and illegal until later on, so maybe you didn't see it.