I think that we all know what evil is. We have a sense of what's evil, and certainly killing innocent people is evil. We're less sure about what is good. There's sort of good, good enough, could be better - but absolute good is a little harder to define.
I had a very famous trainer tell me once, 'You can usually train a wild animal but never tame a wild animal, ever.' They are always going to be wild, no matter what anybody says.
The attempt to redefine the family as a purely voluntary arrangement grows out of the modern delusion that people can keep all their options open all the time.