I dont believe our society has "fallen into moral relativism" by any means. Property crime, murder, pedophilia, adultery, lying, etc- are all still seen by society as a negative thing. My problem is that there is a lack of education of secular ethical systems in the education system. I would rather people know the "why" behind their moral and ethical positions.
I dont believe capital punishment sends a good message to society at large. I dont think our criminal justice system should be based in retribution or justice. I think rehabilitation is possible for many forms of criminality, including murderers. Sometimes its not possible, and in that case we should let them reflect on their wrongdoing until they die. If they want to voluntarily opt for euthanasia, I would be fine with that. But only if they had a living environment that is considered humane.