I think that with DLCs it is bit complicated.
It depends on what kind of DLC it is.
You can have free DLCs, no one can have anything against free stuff.
You can have paid ones and those can make you really mad.
If the DLC enhances the game and makes it better then it is not fair to pay for it. Because you already paid for the game and now to play the same game but better one, you have to pay again.
But if the DLC creates additionaly content which is something completely diferent from the original game, then I think it can be alright to ask money for it. but it really depends on how much it costs then.
For example I did not really liked Skyrim, but I really loved the vampire DLC (cant remember the name), so in this case throwing a few bucks for it seems alright to me.
But anyway I dont expect KCD to have any DLCs