Hetalia is the worst fucking manga/anime of this millennium. You think Naru-tards are bad? Fucking Hetalia-whores are the worst goddamn fangirls of any series ever.
Especially the ones that think it's historically fucking accurate.
Also, you want to know why Korea dislikes Hetalia? In WWII, Koreans were to the Japanese as Jews were to Nazi Germany. The Koreans hate the Japanese because they were treated and killed like dogs by the Imperialist Japanese.
You wanna watch historically actuate anime about WWII? Watch Graveyard of the Fireflies and Barefoot Gen.