"Why? To me this is no different than a person who is against mass murder being okay with multiplayer first person shooters."
I'm not sure it's an apple's to apple's comparison. Multiplayer first person shooting games are designed for mass killing. Minecraft players are playing a game to gather resources to build things. Alice is playing a economic simulation. Obviously she is going to win.
The equivalent analogy would be that Alice gets on to a Counter Strike server, and somehow manipulates the economy where she gets the best guns and all the other players get a knife. IMO, the game will not be fun for the vast majority of the players.
Obviously, the consequence is minimal compared to losing a meal. The only real consequence is that the perpetrator is a big bully and an ass. In real life, we (as a society) would look down on an adult who went to the playground and kicked out all the kids. There are no real consequences for kids to not play in one particular playground, but that's not the society we want.