@Petnavis
I really can't tell if you're trying to make a convincing argument, or if you're just trying to be insulting. "Sheltered 1st world point of view?" I gotta say, ad hominem is pretty weak.
Killing or enslaving anything that might pose a threat is not respectable, or even necessarily effective. Judging people based on what they do, not what they might potentially do in the future, is not something that became a standard because the world is a nice and fluffy place. In a world where people have friends and family that they care about, trying to eliminate anyone who crosses you will very likely cause more problems than it solves. As a group that, self-admittedly, exists in a precarious and vulnerable position, they'd be wise to try to avoid
Bellum omnium contra omnes.
If they're really concerned about safety and security, they don't even need to do anything particularly vampire related. I mean look at real life. It's not like it's impossible to create and propagate a belief system. It's not like it's impossible to create a morally grey institution that is protected by law. Tobacco kills half the people who use it, but somehow that business is still alive and kicking. And they can do it without needing to murder everyone that learns the truth. (the tobacco industry is not exactly a high moral bar here.)
Telling someone to become a slave or die, is not any better than just killing them. It is arguably worse, depending on one's point of view. It's not like making an agreement under the threat of death counts as consent, any more than a signature made under duress counts as valid.
But you know what? Threatening to kill humans that know they exist is only half of what makes them evil. The other half is the way they attempt to control their own kind and limit what their existence can be. "Vampires exist to make more servants."
Telling Nazuna that her only purpose is making kiddies is not dissimilar to telling a woman that her only purpose is making babies. Forget great works, projects of passion, or any kind of self-actualization. It's certainly not the kind of life that Yamori is looking for, at the very least. They condemn each other to live in the shadow of humans, a bunch of paranoid killers always living in fear.
(Assuming that what Yamori is going through isn't just a test.)