You are of course welcome to believe that offerings should not vary according to loyalty either on the ground or in the air but the distinction strikes me as entirely yours and quite arbitrary. Airlines offer a lot of inflight perks to their status members from upgrade priority and downgrade protection to seat selection, free exit rows, extra hand baggage allowance, free blocked seats, free wifi allowance, free access to MCE economy plus and whatever else they call it, and more. Free premium drinks or snacks instead of BoB is just the same as any of those other onboard perks. So as mentioned you can certainly be against it but why this one rather than other onboard perks is not obvious to me.