Final answer:
Participants resented the Nihon Manga Takai organizers because the Japanese history textbooks downplayed Japan's negative actions during its colonial period, particularly regarding the treatment of Korean women and the minimizing of Korean historical events.
Step-by-step explanation:
Participants resented the Nihon Manga Takai organizers for two main reasons. First, the approved textbooks for Japanese middle schools glossed over negative events in Japan's history, particularly during the time when Japan held Korea as a colony and the instances of Japanese imperialism in other Asian countries. This omission was seen as an attempt to whitewash Japan's colonial history, particularly the issue of Korean women being forced into sexual slavery by Japanese troops during World War II, which the textbooks euphemistically described as having been 'drafted' to work. Second, the textbooks minimized the significance of important events in Korean history, such as the independence demonstration in 1919, which was dismissed as a 'riot' despite the resulting casualties inflicted by the Japanese soldiers.
These issues reflect the Japanese desire to maintain a positive national image and nationalistic sentiments, often influenced by groups like the Cherry Blossom Association and the militaristic ultra-nationalist factions within the military, some of whom felt a heightened sense of duty and honor and contempt for civilian leadership.