By your/their logic every nation in the world would be justified in having nuclear weapons.
I honestly can't think of anyone other than proponents of the nuclear power industry that has made that argument. The premise that it is good to spread dual-use civilian nuclear technology does work towards that mindset I suppose, since there is no way to spread the civilian technology without also spreading the most enabling elements of nuclear weapons technology. If you concede the idea that such proliferation is undesirable (as most sane people do) you are left with either rejecting the spread of civilian nuclear power or entering into a state of denial about the link between nuclear power and nuclear weapons.
In regards to Japan I'm certain that most Japanese believe they didn't do so well the last time they attempted to settle international issues with military force, and that they see far more of a threat to their world from the consequences of runaway militarism than they do any attempt by China to invade Japan.
As for your theory about Fukushima, it is far less plausible than simply applying the facts we know to be true. For instance, in 2002 the US came within a hair of having a major incident at Davis Besse nuclear plant. After being notified by the plant operator of the problem the NRC spent THREE DAYS in consultation with the nuclear industry lobbying & public relations group the Nuclear Energy Institute preparing their strategy for how they would release the information to the public.
Three freaking days.
Would you like to see th photos of the football sized hole in the reactor head that the carelessness of both the operator and the regulators allowed?
http://s259.photobucket.com/albums/hh285/taos-eddy/Energy/Davis%20Besse%20Photos/