What’s worrying as it says at the end the failure to confront these atrocities the first time around, combined with rising nationalism in the country does make them more vulnerable to repeating this kind of behaviour again.
My own 2 cents here is considering how a Viking equipped with tanks and artillery would treat anyone they caught way back in 900AD. Japan went from feudal to 20th century without much social development and general knowledge of other cultures was still confined to a narrow (and powerless) slice of the upper class.
The Japanese drive to adopt modern weaponry from the late 19th century onwards was driven by leadership that was aware of developments outside Japan. It's just that they deliberately chose to adopt only technology from the outside world, while retaining the old social structures. <edit>See Justo's reply</edit>
European colonial regimes of the 19th century weren't overly concerned with human rights or other countries' sovereignty either. It can be argued that in foreign policy, Japan followed the example set by the colonial powers. With dreadful sense of timing, it must be added.
China and Korea were first at the receiving end of Japan's renewed interest in the rest of the world. Followed by Russia's defeat near Tsushima.
Focusing on Japanese military horrendous brutality is forgetting the way horror had emerged as a business industry in Europe (beside the forced labor and harvesting on bodies, how many jews or resistants were given to the occupants all across Europe for the small profits ones could make from their leftover belongings?) and how this had perdured all across South-East Asia conflicts in the 20th and early 21st century (remember Myanmar or Encamped China's Muslims? ).
B/w, to illustrate, I am resting for holidays near Bastogne closeby to where the unfamous Malmedy massacre happened.
After the abolition of feudalism in 1871, Japan hastened to create an industrial monster that quickly exceeded the very few natural resources of the country. The inertia generated by the machines dragged the Japanese into a militaristic spiral that only a major defeat could stop.
In 1895 they annexed Taiwan, in 1905 they defeated Russia and in 1910 they invaded Korea to seize large amounts of coal. To save Japan from the effects of the Great Depression the Imperial Japanese Army occupied Manchuria in 1931, giving the Japanese industry access to its numerous natural resources of iron, aluminum, coking coal, soybeans and salt.
In 1933 Japan occupied the Chinese province of Jehol and initiated a large-scale warfare in 1937 that alarmed the international community. Following the clash with the Soviets in Nomonhan, Japan lost access to oil concessions from Northern Sakhalin.
When France capitulated in June 1940, Japan moved into Northern French Indochina and the U.S. Administration reacted by banning the export of essential defense materials: aviation motors, high-octane aviation fuel, lubricants, iron and steel scrap. The embargo was expanded in July 1941 to all grades of oil and the British and the Dutch followed suit, embargoing exports of copper, tin, bauxite, rubber and petroleum to Japan from their colonies in Southern Asia. The Allies were putting Japan in an untenable position that would force oil-starved Japan to seize the oil fields of the Dutch East Indies.
To do this, the Imperial Japanese Army (IJA) should neutralize the powerful British defenses in Singapore and the Imperial Japanese Navy (IJN) should make landings in the Philippines defended by the Americans. The war would be inevitable, the Allies knew, but they did not expect the attack to succeed and were surprised when only 17 Mitsubishi G4M bombers from the IJN Genzan Kokutai managed to sink two of the most modern British battlecruisers in a few minutes.
Justo, you are entirely right about the abolition of feudalism. It was accompanied by other changes in Japanese society, a serious effort at Westernisation of the country aimed at attaining equality with the - can't find a better word for it - imperialist powers of the 19th century.
My contention about Japanese foreign policy stands, though: Japan followed the path laid out by the colonial powers before it. Holding up a mirror.