How we cite our quotes: (Part.Chapter.Paragraph)
Quote #4
"What Valentine wants to do is reverse [the Sword's] alliance—make it an object of demonic rather than angelic power." (2.8.90)
Even objects in this world can be good or evil. In order for Valentine to change the allegiance of the sword, he has to commit a bunch of evil tasks to do it.
Quote #5
"It was a Drevak demon," said Luke, his voice grim. (2.11.114)
There are tons of demons appearing in the book. Not all of them have names, but all of them are gross and evil.
Quote #6
"Werewolves don't hurt people, or each other. Vampires are murders." (2.12.53)
Maia is (falsely) acting like werewolves are saints and vampires are evil here. By this point in the book, not only has she lashed out at Simon, but Jace got into a bar fight with a bunch of werewolves. Both races, were and vampire, are capable of violence.