I agree, though what I would have liked them to touch on more is how they absolutely played with the expectation that the villains might have been redeemable. I was completely expecting them to be and felt like I was just as tricked as the characters in the story when in turned out they really were just irredeemable monsters.

The writing took the expectation of "These characters look like humans and therefore must have human like reasoning and understanding" that's been built up in previous, more contemporary fantasy works and then just played it completely straight in the classic fantasy style of "They're literally just evil".