1. I think you're understanding of this whole issue is limited, at best. That's ok. It's a multilayered issue and the simplifications the media gives actually serve to muddy the issues. You have to look into things more deeply.
2. Did you hear or read Obama's speech? Based on your response I'm guessing that you didn't or you had trouble comprehending it. Here's a link of the transcript (I also recommend dictionary.com for any words that are too long or may give you trouble).
Text of President Obamaâs Speech in Hiroshima, Japan - NYTimes.com
Nowhere was there a denunciation of dropping the bombs. There was a vague denunciation of war in general, but that's par for the course whenever a head of state visits war memorials of one sort or another. I guess you could technically say he equated the losses of the axis and the allies in a sense, but that would show a shallow grasp of the point that was being made: that innocents are the ones who suffer most in war and that man's folly led to unspeakable suffering across the entire world during that time. He equated the dead in the sense that, well, people are people wherever you go and that people suffered on all sides throughout the war. I'm not sure what's so controversial about that.
3. I'll let the WWII vets speak for themselves, thank you very much. I made a point of asking my grandfather, a WWII vet who lost brothers and friends during the war what he thought of the speech. His response was basically "I don't like Obama, but I don't have a problem with it." The only part of it that rubbed him the wrong way was that he felt the reference towards a future without nuclear weapons was a little heavy handed. Overall, there wasn't much notable about the speech one way or another.
You're just wrong about this. First of all, the Senkaku islands aren't in the South China Sea. Second of all, China hasn't and isn't seizing the Senkaku islands. Heck, Japan has nothing to do with them other than liking to throw the fact that they legally own them in China's face every once in a while. The islands are actually administered and overseen by Taiwan (the closest place with the best geographical claim to the islands) with Japan's blessing. The closest China has come to seizing the Senkaku islands was a few years back when some Chinese sentiment against Japan was being riled up to distract from ongoing corruption charges to party officials and a rag-tag group of pissed off fishermen sailed some of their boats around the island a little bit before the Chinese government had to issue strong warnings for them to go home.
You don't realize that disputes like this over useless rocks in the pacific are fairly common, do you? Japan and South Korea have a similar dispute. China and South Korea have one. Taiwan is involved with a few of their own. East and Southeast Asian countries have had pissing matches like these for centuries.
China's toeing of the line is a problem and I've never suggested otherwise. But getting the Senkaku Islands dispute confused with other, much more heavy handed moves they've taken recently shows a poor understanding of the geopolitics of the area. Suggesting that Japan is under threat of having territory seized because of a hundreds of years old pissing match about those islands isn't a fair or accurate representation of the situation. You can keep arguing until you're blue in the face, but it's just not true.
China's actions in the dispute have been nothing but verbal condemnations and angry looks. They know if they ever made any overt action to seize the islands, it would lead to world war 3. It's not worth it for them when there are other more valuable places they can exert their power without having to worry about triggering a multinational conflict.