@Simbloom
Seems pretty logical to me.
You don't give a shit when a stranger dies. yeah you might say something like "Oh how bad, I feel bad for him" but in reality it doesn't affects you in the slightest.
But if someone that you are familiar with dies, of course you would feel remorse.
the same applies here. He killed people, is normal for the ones close to them to get revenge by killing his family, but that doesn't mean he can't take revenge himself by doing the same thing.