Well largely because, while I like orcs, I want to stay away from them in my games and home brew settings. Because we use them as de-facto villain fodder too often. I’m a big fan of replacing orcs with humans. The general idea being that anytime you replace orcs with humans, players stop and think about what’s going on instead of immediately dashing into action. And players rationalize and talk to humans but just murderhobo orcs. And that makes for boring gameplay, because NPCs and even enemies should have motivations and yes, I think your players should know those so they can act tactically about them.
So why include horrible cannibal men at all? Well, a two reasons. One is the horror aspect. This could be you, that somewhere deep within us we may cave to this act in desperation, and then find perverse pleasure in such. Donner Party Annual Family Reunion and Barbecue, etc, etc.
The second is that, while I think having your players question the motivations and actions of villains and monstrous NPCs is good, the genre of fiction the game is based off of, and thus the heart of the game, is Pulp Fantasy. Pulp Fantasy has a lot of swashbuckling action and fights, and the game itself mechanically comes from war-games. Combat is, and should be, an inevitability. I really don’t think PCs should be able to talk their way out of everything; that’s lame. Hell, a whole gamer type is known as “The Buttkicker”. So obviously I want villains who are morally bankrupt and my players won’t think twice about engaging, as well as likely to start a rumble due to hunger, perverse desire, or whatever other reason they have to eat people.
So I’m gonna take a moment to mention to all three of you that read this that I’m moving across country, and across a whole continent as a result, from the South East to the far North West. It’s gonna be a long drive, and hopefully I’ll be able to write a good bit as I drive and ride across. This is part of why I’ve been quieter than usual and also why I may get quiet again as I transition into a new-old job, which should prove interesting.