You're equating your western values of life while the enemy does not. If you'd read the entire thread, you'd see I made it clear this is a tactic to use against jihadist butchers.
So what you are doing is picking and choosing who's family we execute and who's family we don't?
Understandable if the family has similar connections to terrorist organizations, but no parent can control the actions of their children once they are adults. They are responsible for their children when they are children.
Should we have killed the father of Timothy McVeigh for the OKC bombing? His parents divorced when he was ten years old and was raised by his father. From what I've read, his father was never in any trouble yet alone being a radical.