I think PETA need to re-think their positioning on this one a bit...
Maybe think about taking the word 'option' out of that sentence.
See, Peta...
When someone is given the option to do something, they don't have to do it, and if they don't have to do it, then it's up to the player.
And even then, they'd be sacrificing themselves for the sake of a virtual rat. Is PETA advocating suicide for the protection of imaginary animals?
I'm sure the developers don't advocate or encourage the slaughter of small land mammals...
It's an utterly insignificant, tiny segment of a lager whole which is filled to the brim with killing people.
Had it been an animal slaughter simulator, then yes, you'd have grounds to be concerned, but since it's a small part of a game which has nothing to do with the focus I think we're OK.
Video-games aren't going to turn us into animal-hating psychos just yet.
[As a quick after thought]
Where were PETA when Duke was stompin' rats to hell?