If you attack me and I shoot you, you're to blame for your death, not me.
If a country attacks me and I counterattack to make sure you can't attack me anymore, you remain at blame.
There are details, like deliberate civilian attacks vs collateral, but at the end of the day, the duty of a country is to protect it's own citizens, and not the citizens of the aggressor.
I'm guessing we disagree on who is responsible for those deaths.