Only way I can get negative Karma is my stealing stuff, I'm like the Desert Jesus when I'm trying to be neutral.

I figured if you kill some traveling merchants in cold blood you'd get bad Karma like in F3, but I don't! I can murder a whole town and not get 1 point of negative Karma, is this a bug or what?

Not hard to do, If you don't mind refraining from killing Powder Gangers or Fiends. Kill generic NPC's and steal..alot. Generally be a nuisance.

Edit: Must be a bug because I get negatice Karma sometimes and others I don't. In this game it's hard to be evil.

I'm not trying to be evil I'm trying to be neutral.

As I said the only way I get bad Karma is by stealing, I cant take out a whole slew of Wasters, a entire town, and not get any negative Karma.

As far as I know stealing and killing are the only save the select few responses in certain quests. You could get the cannibal perk. It's a considered a crime against nature and gets you bad Karma no matter where or when you eat it.