Japan has had a very clean record in regards to using it's military to solve territorial disputes for the past 70 years. Meanwhile China and S-Korea have been upping their anti-Japanese rhetoric for the past years bringing up world-war two at each and every turn to justify what they;re doing. And here's a fun but maybe inconvenient fact for you: One of the main reasons that Abe is finally building up Japan's military is the fact that the U.S. government has been bitching for years for Japan to play a larger role militarily in the "solving of international disputes". Meaning sending people over to Iraq to aid the U.S. in their war etc. Now you can't do that under the constitution and the Japanese people and governments have been opposed to it for a very long time. Now in fact, there has been a lot of protest against the repeal or "reinterpretation" of article 9 in Japan. Try and follow the news in Japan every once a while, it might be an educating experience. Japanese people who ordinarily would want to stay as far away from a protest as possible are demonstrating in the streets. Not just about this issue either, nuclear energy is being protested, everything.
As for China, they're not as innocent in all this as you lead everyone believe to be. There are a lot of countries with territorial disputes with China. Read up on it if you like. https://en.wikipedia.org/wiki/Territorial_disputes_in_the_South_China_Sea
Japan has been as much a threat to Asia as germany has been to Europe in the last 70 years. It's literally inconceivable that even with building up a militarily they would seriously consider a militarily conflict with China or South-Korea. No-one serious in Japan thinks they can militarily win a war against China or SK or even consider it a remote possibility.But it fits nice in the picture of the anti-Japanese propaganda machine that's been going up for the past few years. And people like to gobble it up in the west because of the memory of how terrifying Japan with a military used to be. China on the other hand has been massively building up it's military and actually does take an agressive stance when it comes to territorial disputes. They haven't actually fucked around when it comes to Vietnam or the Philippines either.
What do you expect the Japanese to do when Chinese send boats way out into Japanese territory, unilaterally declare a larger part of the sea their airspace where every aircraft needs to identify themselves to the Chinese at the risk of being SHOT DOWN and has disputes with every country that even remotely share a border with them?
Before the rise of China your position may have actually been tenable if you're not just another anti-Japanese racist. But the reality with China on the rise not just economically but also militarily is changing. South-Korea is getting closer and closer to China and politically distancing itself further and further from Japan.
I think Japan is just coming to terms with a very inconvenient political reality. You can't keep relying on the U.S's word that it's going to protect Japan in case something happens. Or maybe you can, but only if you are willing to participate in U.S. "Democracy promotion" in other countries as well. So yeah the repeal of article 9 is a problem. Yes, Abe isn't the nicest guy either but whatever his ideology and however unsincere his apology he is adapting to the new reality in Asia.