Honestly, I think the Japanese deserved it. If you see the war crimes committed by the Japanese in World War II, you will know that the atomic bomb was right.
Saying that the Japanese people deserved it comes off as hateful. Not every Japanese person was complicit. Like I think it was pretty clear Japanese children were innocent casualties.
By standards of the day, absolutely. Today, probably not.
From the military and strategic standpoint of 1945, using nuclear weapons to rapidly end the war was considered justified, necessary, and effective, especially given the precedent of widespread strategic bombing and the anticipated cost of a full-scale invasion.
While moral dissent existed, it was overridden by the dominant goal of ending the war quickly and decisively. A goal that, in the minds of U.S. leaders, justified the use of overwhelming force.
It's a tough question, it was total war, all the civilians were working to support the military goals. Japanese supposedly had a very militarized society (1). The concept of total war adopted by the expansionist axis powers meant that the allies had to fight back in the same way, namely use strategic bombing (2) to lower their morale and destroy civilian infrastructure and industrial targets which aided the war effort.