Yes. That was an act of war. It was a war crime. It does NOT mean we have to respond in kind with the same sort of barbarism. Target the leaders. Target the army. Target the political infrastructure of the countries who back terrorism.
What would you have us do? Become like our enemy? Drop a nuke on cities full of women and children?
In any war, civilians will die. That doesn't mean we should target civilians.
Yes. I would have us win the war against those who declared war upon us by bombing our innocent citizenry. Thank God it isn't up to you to defend anything.