That is not what was said. The headline from the original AP story that has been paraphrased and copied by other press is quite a reach, intended, I assume, to sensationalize this.
The issue Abe spoke to was a refresher on the constitutional and policy issue in general. Many people have forgotten, or are unaware, that Japan has had a policy that a pre-emptive strike against an imminent attack that could not be stopped after initiated was established in 1956, not now.
The issue he wanted discussed was that Japan has no capability to act on that policy, regardless of what nation it could be. Japan has no offensive capability to meet that requirement.
Discussing and addressing the question of building that capability, and framing it around the unusal constitutional situation and perception of the public in Japan, was his point.
Oh, how I hate the press more and more...