Bit of a powerlevel, but I'm married to a Korean and have lived in Korea for eight years. The subject, and that of the colonial era in general, are still hot topics in modern culture. Needless to say, anti-Japanese sentiment is high. Students of mine praise and laugh about the atomic bombings and have also seen store clerks proudly wearing big pins calling for a boycott of Japan and calling Abe the devil. Not to mention all the mentions of the Japs being savage, dirty monkeys.
Bob is a known defender of the glorious land of Nippon, so he probably is not aware of the full extent of what Japan did. There are literally dozens of Korean made movies about the colonial era and Japanese crimes, but I imagine he must hesitate to view them seeing as how Mario was birthed in Japan and all.