Poor analogy. Religion is a belief structure, not a physical quality. Even though you can't choose your physical attributes, you can still choose what you believe in.
But to humor your argument, murder IS a distinctly christian value. There are numerous instances where the bible commands the death of people for trivial crimes. You can't disown somebody as soon as they do something wrong. How do we know it wasn't his christian adherence that caused him to kill in the first place?
Anyone arrogant enough to reject the verdict of the judge or of the priest who represents the LORD your God must be put to death. Such evil must be purged from Israel. -
If a man lies with a male as with a women, both of them shall be put to death for their abominable deed; they have forfeited their lives. - Leviticus 20:13
Whoever strikes his father or mother shall be put to death. - Exodus 21:15