Look a little harder then, and I would like if you stopped trying to derail threads via personal attacks.
Yes I have, and I know about the difference between creatures like feral ghouls, and NPCs like raiders and non feral ghouls, and the limitations of both. As I was saying, they could have simply made the feral ghouls into NPCs like the non feral ones, and given them the non-feral ghoul skins, if they wanted to. They did not, even though they easily could have like Obsidian did with many of the ghouls in Searchlight, as I pointed out. Hell, Bethesda made several "non-feral" type NPC ghouls hostile in Fallout 3, such as Gallo, but chose not to make the others work the same way.
Ghouls are the way they are because Bethesda wanted them to be that way, not because of technical limitations. They didn't HAVE to make feral ghouls creatures, nor did they HAVE to give ferals and non-feral different skins. That they did so was because they wanted them to act different, and look different, by design. Most likely so the player doesn't accidentally shoot a non-feral ghoul because they have the same skin as feral ones.