I'm a sensitive person, but I don't see what's wrong with killing animals in video games which are based around killing humans. In real life, given a choice between killing an animal and a human, I'd take the animal ten times out of 10.
Again, I'm not supporting people who want pets to be in GTA, I'm just saying that it shouldn't be such a big deal, especially when we all go around killing people with dildos and screwdrivers and all this in video games.