After watching this video, my opinion on orcs has been solidified. In my headcanon, Melkor took elves and technically killed them, leaving behind a "living" body. The body had only animal desires, of course, which led to fear, violence, looting, and hate. Some of the less-evil traits shown by orcs, such as wanting to be free of a higher power and willingness to exist with each other in general, can be associated to animal desires as well. The final seal in this scenario is that Tolkien did not want orcs to be irredeemably evil. You can take even the most aggressive cat (an example of exclusively animalistic desires) and make it feel compassion, love, and loyalty to a certain extent. The same, I would argue, can be said for orcs.