I'm saying that an emotional attachment doesn't affect whether I believe it's moral to kill him. It causes me to place a higher value on my dog such that I value him more alive as a pet than dead as food. Were I starving, I'd value him more dead as food. This value doesn't change whether or not it's moral to kill him.

As an analogue, I might have a car I like. The car could be worth more to me than its fair market value because of an emotional attachment, and that may mean I prefer not to sell it. If I'm in dire need of money, however, I'd probably sell it anyway.