If your point is that what these people did was reprehensible, of course it was. But opposition to capital punishment isn't about warm fuzzy feelings for the guilty. It's about our commitment to the principle that God is the author of human life and only God has the right to take it. 

The death penalty is only justifiable if it is the only means by which to protect society from a dangerous person. Revenge isn't an acceptable reason for it and neither is revulsion at the crimes of the guilty.