A fine restaurant in town has a wine list, but heck the prices are pretty high and they don't have the specific wine we like. Do we bring our own? Practically no one thinks twice if the restaurant charges a corkage fee, and practically no one would reduce the server's gratuity by the amount of the corkage fee.
Disney offers room service, restaurants, counter service eateries and even their own grocery delivery to villas and suites, but heck the prices are pretty high and they don't necessarily have the specific items that some people like. Yet, some people think that Disney charging a fee for bringing your own food warrants reducing or eliminating some other cost that the guest would otherwise incur.
Like many other things, the root cause of the conflict is that never-ending battle between Disney and its guests, with Disney working to do what it is supposed to do - earn full value for its investors - and guests doing what they're supposed to do - pay as little as they legitimately can for what they want - and Disney's employees caught in the middle. And the problem is made worse because Disney is expected to do things in a way that makes the guests feel like they are always right even when they are not. It is the image that Disney tries to project that confuses things. Take that out of the equation and the situation would be clearer.
Yes, it grates on guests to have to pay a fee for a service that used to be included and then put a tip on top of that. Yes, the bell staff has no choice about the fee or what work they're assigned. Yes, the bell staff's arrangement with their employer isn't the guests' problem. All three things are true. So where is the weak side of the three-part argument? It is in the lap of the guests, because a guest's upset about the way a service is offered should lead that guest to decide to do without, not make a third party pay for their upset.
Our choice is going to be to do without outside grocery delivery. It was an advantage that Disney let us take for a while and now they've made it barely worth the bother. Mission accomplished. If that means we have to downgrade from full-service to counter service for a meal or two each trip to make up for the added costs, we'll do that.