Haven't say that. Tell me what you think about it.
I told you there's bloodthirsty apes in the sewers to balance out the situation if rats weren't hostile but you just bypassed that argument. For me it's weird that someone can think of non-hostile rats being a problem in an area where you can get randomly killed by another player with powerbuild designed for combat.
Plus the rats are no worth to lvl24 chars who wish to use the sewers as strategic advantage in competition situation against other players.
In addition pve and pvp areas should never be combined because fighting players and npcs at the same time is really messy, which was proved by the militia issue and generally when it comes to pks jumping in your farming encounter.
The rats are clever animals and FEV maybe made them even more cleverer. For them gunfire means food. Killed rats lure the living ones from lower levels and they eat the corpses. Well, they also eat ocassional visitors, if not each other. They also have manti to hunt and eat. As for not patrolling sewers, they have no scripts, or maybe they are territorial.It doesn't bother me. I'm not even complaining. Are you complaining about rats being hostile?
See what talking about immersion does: nothing. We could talk endlessly about the fallout lore and get carried away from the actual subject and what's happening ingame.
Players who are dealing with features in daily basis only care that they work fluently and enjoyable way. Immersion is just a top layer to make things look at least credible. Players who try things only few times may find immersion really important, whereas experienced players just bypass it and concentrate on their goals. Who should the features support most: those who are involved with them daily, or those who check them once or rarely?
So if the rats don't bother you, why are you telling they should remain the way they are? If you would have no problem them not being hostile by default, what's the issue?