Lucifer and his dissidents were cast out of Heaven so how come there are so many anti-angels left?

Good point. Though maybe all angels are just a step away from becoming like Lucifer. They all see power hungry so maybe that's part of their inherent nature (an it's maybe the journey that they need to take - to learn humility and compassion once again. Cas seems to be the only understanding that…)

Humans seem very lowly to angels. Saving their lives is the least of their worries. Securing vessels (even though it could possibly kill them) seems to be the most important thing to them. I wonder why their light is white - there's certainly nothing pure about them.