It's not arbitrary, but it does follow a different reasoning from that you lay out. On the level of your analysis, one ought to perhaps have the greatest distaste for stinking cloud... but our analyses are not the same.
I find the minions mechanics distasteful because of what it is saying about humanoid minions, not because it is pretending to any specially horrible destruction of them. I'm uncomfortable positioning certain humanoids as objects for mass slaughter. That is separate from what I do or do not feel about pretending to inflict horrible ways to die. And in 4e, even fireball isn't mechanically bound to doing that.
Some folk seem to say they see the 4e game mechanics as a sort of undifferentiated blur, or to be accepted all or nothing. Although I agree that the game text overall is significantly important context for the interpretation of the mechanics that make it up, D&D game texts are extensive and diverse enough to that individual mechanics can be differentiated. For instance, the 5e DMG contains some mechanics that fit process simulation, even while the PHB contains many others that are not.