Sometimes, one has to make choices that are hard, but for the good of all. That is what Giles has done. I don't blame him for doing it. Sometimes, one has to do what has to be done.
I have no problems with seeing Dawn killed off. I despised her character from moment one and at times have come close to hating her the way I hated Spike. But showing how her death would affect others around her makes her--finally--more than the crushing burden she became for Buffy and the sad reason the Slayer threw away her life. Thanks for this insight.