There are definitely "morals" in the game, violate the water ritual and find out! But I've been lazily designing a taboos mod since I've been interested in pushing the game's factions sub-system, and mod support just got added for float and int modifiers for factions, so it should be theoretically doable now. Game would just detect the eating of "bad" (ie, humanoid) corpses the same way it detects stealing. Loss of rep for most factions by eating humanoid corpses (except cannibal faction, maybe Children of Mamon), maybe reduced rep loss if carnivore defect is chosen. Would be most interesting to also change how the cannibal faction prioritizes eating vs killing, but that might be too complicated to easily add; maybe add it into the game's version of idle behavior for NPCs?

But also would need to add some code for allowing humanoid corpses to be butchered into something, plus XML code for the new food items created by the butchering of humanoid corpses. Plus probably some sort of personal modifier that tells you that you're a dirty cannibal (even if other factions don't know, which may require a second modifier for outing yourself as a cannibal). Bonus points if the personal modifer acts like an addiction, some sort of extra food bonus BUT a penalty for going too long without satisfying your cravings...

Edit: Interesting, game (or at least wiki) has a separate section for humanoid corpses (how convenient!), but dromad corpses aren't classified as humanoid... so it's not murder to kill Tam? Still can't butcher the dromad corpse into anything, but still, odd. I'll have to double-check the XML code first to be sure, but might have to make a bug report for this.

Edit 2: Interesting, dromads are classed as humanoid, but the corpses aren't, and the dromad corpse item XML info is stored in the creatures XML instead of the normal items XML. Technically a bug, although any in-game effects are negligible. I'll still drop a bug report, but likely won't get fixed until the 1.0 pre-polish patch (if at all).