Avraym's argument is that SE has seemingly created a system where it is optimal for everyone to belong to the same Grand Company. Everyone would then always enjoy the maximum drop rates. People belonging to minority Grand Companies may be shunned because their inclusion would cause a negative effect on the majority. You can say they lose their bonus, or that they incur a penalty. Either way you look at it, though, isn't not an incentive to break the mold and join an unpopular Grand Company. This threatens to further solidify Ul'dah's position as the primary city of Eorzea despite the new transportation.