Hiroshima and its Justification

I found the following blog post showing photos of the effects of Hiroshima and some commentary and explanations. The Digg post with people's comments is here.

There are two points here for me. The first is indeed how this event has been all but forgotten. I am comparing it to events like the holocaust which still is the subject of many movies and books. Why is it that this horror is not as well `publicized'?
The second point is actually something which I don't know and I would like someone to tell me. I have heard many people use the argument that "if we didn't drop both of those about 5 times more people would have died in a mainland invasion (including civilians)". Is this correct and would it have happened with certainty? It seems to me that it is simply a an excuse or justification for the annihilation of such a massive body of humanity. Actually this is also a comment that one of the profs here at uni (makow.) made to me one day when i dared object to this attack. Now I know what to answer him. Japan was going to surrender anyway.

Here are some comments from people on Digg that I thought were interesting:

The United States Strategic Bombing Survey, after interviewing hundreds of Japanese civilian and military leaders after Japan surrendered, reported:
"Based on a detailed investigation of all the facts, and supported by the testimony of the surviving Japanese leaders involved, it is the Survey's opinion that certainly prior to 31 December 1945, and in all probability prior to 1 November 1945, Japan would have surrendered even if the atomic bombs had not been dropped, even if Russia had not entered the war, and even if no invasion had been planned or contemplated."
http://www.ibiblio.org/hyperwar/AAF/USSBS-PTO-Summary.html#jstetw

He proposed the scenario where Iraq indeed had weapons of mass distruction, not chemical weapons but Nukes.
Just like the US was able to fight off the invasion of Japanese, Iraqis were able to defend themselves against the US intrusion and push coalition forces all the way back to the US border. They knew US wouldn't just give up and more people on both sides would continue fighting, so they dropped 2 nuclear bombs in 2 non-militarized cities, to put an end to war.
Would that be justifiable? Would you calmly accept the fact and nod at the loss of your own men for what's referred to as a "lesser of 2 evils"?

"I do not know with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."
-- Albert Einstein, in a letter to Harry S. Truman

do you really think this is an excuse? then anyone with enough power should bomb anywhere, and then say "well, if i didn't do that, i was gonna do something worse. thank me."

No doubt many more lives would have been lost in a ground invasion, please note that I'm not trying to deny this. It's just interesting that this intimidation tactic (one could say its purpose was to instill fear in the Japanese government) is deemed a necessary evil, whereas 9/11, yielding a fraction of the damage, was considered abhorrent and terrible and wrong.
One is called strategy, the other is called terrorism. What a funny world we live in.