Why would American troops be so relieved to hear that the Americans had dropped the atomic bomb on Japan?

That would mean that the war would end quickly with the invention of such a powerful weapon.

I believe the Americans would be relieved, because the Japanese dropped a bomb on Pearl Harbor, killing americans on the boat, which was a sneak attack by the Japanese. So, by being able to return a bomb that was dropped on the Americans and doing the same back for loved ones lost. Would make americans feel relieved.