If you are for the death penalty when your emotions are high, you are for the death penalty period. People who are against the death penalty don’t go on the record in support of the death penalty, because it’s a principle, not something that you only stand for when it is convenient for you.
If the death of an animal is enough to make you flip, you’re probably going to side with most death sentences since they relate to the murder of human beings.
Someone could murder members of my family, and I would still be against the death penalty, because that’s who I am. You’re not going to hear me calling for anyone’s death, regardless of my emotional state, because I know that doesn’t solve anything, and it is bad for our society as a whole.