hawkeyefan
Legend
The notion that a Robin Hood-type background is a trap option - if it were true - would be a sad indictment of a relatively conventional mediaeval FRPG.
It seems obvious, though, that the background can work perfectly feasibly exactly as written, and that it is only and exactly the sort of GM behind-the scenes decision-making described by @Manbearcat that undercuts its utility.
I think it takes one of three things.
Not realizing that overriding the ability has rendered a player decision moot, especially one that, outside of spells, grants the player a shred of authority over what happens in the game world. I think this is likely the most common reason.
Anger and or frustration at having to cede authority to anything but magic. That any rule in the game would simply just work without the GM's approval without the lampshade of "but it's magic" is simply unacceptable to a certain set of GMs.
Willful negation of the ability to further an agenda of some sort... some preferred outcome, some setting aesthetic, some predetermined element that is perturbed by the ability.
All of which are examples of poor GMing, in my eyes. The first is about an instance of poor GMing... the second is about ingrained ideas that lead to poor GMing. The third could be either.