Mark CMG
Creative Mountain Games
Now I've never heard of a game breaking up over an argument about an NPC's body odour, but here is a more typical example of the same phenomenon that can and does break up games:
Player: "My guy attacks him.:
GM: "Why?"
Player: "Because he's evil and I hate evil!"
GM: "But he didn't detect evil when you cast your spell."
From here, it can be a pretty short path to a busted game. Is the GM going to override the player's authority over his/her PC's volition?
The GM should be describing the consequences of the players' actions.
In the second example the ref is questioning the player's motives. That's a big no no IME. I'm not saying that questioning a player is wrong on the ref's part, but "Why" specifically isn't asked. How? Who? What? Where? When? Sure, any of those clarify the attempt.
Yup. That's just bad GMing. Certainly the GM should be asking for more information so that the consequences can be accurately described but that information needn't come from the question of "Why?" (Unless the GM believes that the player misunderstood the descrption of the detect evil spell or the consequences from using the spell and finding no evil.)