I would have thought that actual Japanese people would more inclined to fair to their own history, than westerners.

I don't want to speak too loudly as there's still a lot more I need to learn about this subject. But in general you'd be surprised to the extent to which the Japanese adopted the Western narrative of themselves.

I think the quickest way to explain it is to say that in the non-Western response to the obvious Western military and economic superiority of the colonial era, there generally developed two opposite extremes: radical nativists who wanted a purification of their society of perceived Western influences; and radical modernist who wanted the diametrical opposite: to purify their country of traditional influences and fully embrace, what they perceived as, Western modernity. And the latter could become very extreme, Ian Buruma mentions one Japanese scholar who suggested the Japanese should all convert to Christianity and interbreed with Europeans as much as possible.

Now in practice the vast majority weren't either-or one of those two, but were some mixture in the middle. But it certainly doesn't strike me as opposed to anything I've read on the subject for a Japanese person of the WW2 era to identify sufficiently with the radical modernist position to speak denigrating of their own country from a century ago.

If you want to read the actual expert take, the above mentioned Buruma writes extensively on this in Inventing Japan and Occidentalism. Though it's dealt with in any respectable history of Japan's rise to modernity, as the grappling with Western narratives of Western superiority is a key feature of that whole historical period.

I guess this officer refered to the Meiji period which is, as far as I can understand it, how it is presented today to Japanese school kids: a period of transition between a feudal system into an industrial one. It was radical and pretty successful.

It happened at the end of a civil war between the shogun, a military ruler, and the emperor. The emperor prevailed and used this victory and his newfound legitimate position of power to make the transition, stripping most of the aristocrats from their prerogatives. Japan at this time (~1870) still had not made its industrial revolution. It was late compared to western powers, but in this position, we have several historical examples showing that a pretty directive and competent government can make the industrial transition quickly.

To substantiate your quote, here is a passage taken from the wikipedia (which cites the source):

In 1885 noted public intellectual, Yukichi Fukuzawa, wrote the influential essay "Leaving Asia", arguing that Japan should orient itself at the "civilized countries of the West", leaving behind the "hopelessly backward" Asian neighbors, namely Korea and China. This essay certainly encouraged the economic and technological rise of Japan in the Meiji period, but it also may have laid the intellectual foundations for later Japanese colonialism in the region.