>>because hide is inherently a civilized skill.<<

Mostly true. Thieves can hide on plains and sometimes in other places. Some creatures in the game hide in their natural environment rather than camo. This could just be older area code, but it rings true that if there are shadows somewhere, something can hide. Less effective than camo, yes, but it suits a thief or assassin. Especially since assassins can hide in a lot of places thieves can't in the wilds.

Maybe the real solution to this would be to take away chameleon altogether from assassins/thieves and give them the kind of hide assassins can use.