Then why dont i get penalized for looting random raiders and other assorted "bad guys" in the wasteland?
Because you don't get bad karma for taking from those who invariably attack you on sight. You also don't get bad karma for taking from corpses. Basically, if it shows up in red and says "Steal" taking it is going to give you bad karma. Similarly, if it says "Pick Up" instead of "Take", steel yourself for something script-based to happen.
The Powder Gangers are a faction, one which the player is capable of aligning with if the opposite quest to "Ghost Town Gunfight" is completed. The difference is that one is always hostile, the other is only hostile under some conditions.
-Nukeknockout