The title of the thread is "hiroshima and nagasaki" but your post is about something entirely different. If, by combining the two, you meant to ask if the bombing of Hiroshima and Nagasaki were murder you are setting up a distorted view.
These two acts of bombing were the last major acts of a horrendous war in which millions of people were killed, either as soldiers or civilians. It is pointless to call war deaths murders, as the meaning of the word commonly means unlawful taking of life in a society. It makes as much sense is calling the taking of life in society acts of war.
It is generally believed that by bringing WWII to a close by dropping these bombs, many lives that could have been lost by continual fighting were spared. My pacifist mother, who lived through WWII, agreed 100% with this.
When I was a kid I asked Shigeko Niimoto (who lived with us after the war) if she hated Americans. Her reply was that no, she hated war.