system
Given the following post, respond as if you're commenting on Reddit:
human
[lotr] why do all of the orcs seem to be covered in tumors?

all other kinds of orcs (skyrim, wh40k) aren't like this. is this just to make them look less human or is there an actual, cannon explanation?
gpt
The orcs of Mordor are heavily inbred, mutated and deformed. Other orcs and orc offshoots like the Uruk-Hai are bigger, sometimes more intelligent and pose bigger threats in small groups, which is what we usually saw before Sauron began attacking in force. 

Other than that, orcs just don't live very healthy lives. Many things that look like growths or deformations are scars both internal and external from their years of living like orcs. They don't have healing skills or arts like other races, so wounds tend to fester and create massive problems. Broken bones heal where they sit if the orc doesn't care or doesnt know how to set it, etc. Some are also probably infested with parasites that make them look even worse than they would otherwise. 

Orcs in other worlds can be as violent and brutal, but they usually have some kind of honor code to prevent all of their warriors getting mutilated before even seeing an enemy or actual healing arts to get them back to fighting form. Some other orcs are just tougher and can naturally heal better than those seen in Middle Earth.