I think it has more to do with telling friend from foe than the whole "Murder is A-OK" thing. I say this because I've watched the following scenario play out time and again while sneaking around goblin sites.
>Goblin asks Troll to identify itself.
>Troll can't reply because trolls cannot speak.
>Goblin assumes Troll is an enemy because it doesn't identify itself.
>No Quarter combat ensues because goblins must kill enemies and neutrals.
>Goblin cancels Being Alive: Picked fight with creature over four times its size.
>Troll is now an enemy of its own civilization, but still a member of that civilization.
>Troll is now surrounded by enemies
>[ETHIC:KILL_ENEMY:REQUIRED]
>Rip and Tear
>Random Beak Dog Joins The Fight!
>Troll #2 uses the distraction to run up and punch Troll #1 to death
>Another Goblin asks Troll #2 to identify itself
>Trolls still can't speak you idiot
>tfw
My take is that we're witnessing a loyalty cascade caused by trolls failing to respond to friend-or-foe requests. It's understandably hard to declare allegiances
when you can't speak, and that's sort of a big problem. I've started giving trolls the ability to speak and it seems to fix the problem, but it's hard to say for certain when you have to factor in legalized murder and foreign spies who may or may not be getting found out and killed in front of you, all while staying hidden in an entire city of green idiots who want you dead so as not to contaminate test results.