But I will add a defense to the arguments listed in the Extra Credits video. Think about it this way: It is actually impossible for anyone to be inherently evil or good with no choice – because evil, like good, requires free will to truly qualify as good or evil. Saying that someone is inherently evil or good is like saying that the water was dry, or that a person is freezing hot. It’s a contradiction. In short, “evil” orcs that have no choice in the matter are not evil, but are instead like lions or sharks. They can’t help it.

That's the point, Brain Dead. Tolkien felt bad about killing people, even people who sided with evil, so he invented Orcs so he wouldn't have to feel bad about it.