I agree, I don't think it should be considered stealing if they are your enemy. The Legion and the Powder Gangers hate me, I get "good" karma for killing them, yet loose karma if I take their Brahmin steak after killing off the camp? It makes no sense. Also, I think it is dumb that it is still considered stealing from a NPC if that NPC is dead. For example, I had Boone kill Jeannie May, yet if I go to her home, it is still considered stealing. Does anyone else find this dumb?
I did.
I don't think you get bad karma for stealing Jeannie May's stuff after she is dead. It shows up as red but it doesn't seem to give bad karma, just like opening the door of Benny's suite.
I'll admit, I steal a lot. Any weapon, Weapons Repair Kit component, skill book etc. that I find. I usually make up for it by hunting down the respawning Fiends in the Fiend Territory. You get as much good karma from them as you do from Ghouls, but Ghouls don't leave much loot.