I mean you seem to be a troll account but on the off chance that you are asking this in sincerity, I’ll bite.
For the record, I’m not US American. I’m a passport-holding South Korean citizen. And I will be speaking on the entire Hetalia franchise (webcomic, manga, game, anime) and not just the anime.
The author - Hidekaz Himaruya - is a known anti-Korean nationalist. Like one of his comics before Hetalia was called MoeKan (literally: Moe Korea) where the Korean protagonist was portrayed as angry at Japan for no reason and violently attacks the Japanese character every chance she gets. If you know anything about Asian history - Koreans have a valid reason for disliking Japan considering the decades of brutal colonization where Koreans were murdered, raped, and had their culture forcibly erased. But Himaruya literally portrays this sensitive issue as “Korean youth are taught by their parents to hate Japan for no reason [because Japan didn’t do anything wrong] and are violent and nonsensical.” Sena, the main character, is dressed in really outdated hanbok (the manga is set in the 2000s and was written when he himself was studying abroad in New York) while in contrast the Japanese self-insert character is wearing modern Western attire. This is… literally one of the talking points of Japanese far-right nationalism where Japanese right-wingers believe that Korea was uncivilized and only found modernity through Japanese occupation.
The main character from MoeKan would go onto become an inspiration for APH Korea. He actually thought about just using her character again for Hetalia but changed his mind and made APH Korea male with most of the same traits. Again, Korea is portrayed as an idiot younger brother type who claims that he invented things for no reason. (Notable is the one strip where APH Korea claims that he invented hanzi and APH Japan muses “if you could read kanji you wouldn’t say that”. No one Korean would actually claim this. I know because I literally went through the South Korean schooling system and learned Chinese characters in class. If you actually also look up the history of kanji… you’ll find that it’s a Korean scholar from Baekje who brought it over to Japan to teach people how to read/write.) “Koreans claim they invented everything” is literally an anti-Korean stereotype in Japan. Much like how “China is obsessed with bootlegs” is an anti-China stereotype.
There’s literally a strip where APH Korea demands APH Japan apologize because he has photo proof of APH Japan being bad. Japan asks to see the photo and the brutal colonization of Korea is portrayed as “Korea and Japan getting along when they were children”. This is explicit historical revisionism. Murder, rape, and cultural genocide is whitewashed as “that time Korean and Japan got along but Korea still wants to complain about it.”
Hetalia’s treatment of colonized-colonizer relationships has ALWAYS been shitty. Even beyond how Himaruya portrays Korea - Seychelles, an African country that was colonized by England in real life is shown with…. a collar around her neck. That England puts on her. A white personification of a colonizing nation is literally depicted putting a COLLAR on a black personification of the colonized country. Not only this straight up minimizing colonization but also… literally… makes a joke out of the fact that historically Black people have been forced into chattel slavery.
Colonized countries are almost always portrayed as obsessed with their colonizers or secretly in love with them (Korea-Japan, Belarus-Russia, etc). And while other countries’ traumas are treated as comedic material (Korea’s sovereignty over Dokdo being portrayed as Korea sexually assaulting Japan’s body, the invasion of China being played off as a physical gag) - Japanese trauma is never treated the same way.
Could you imagine if the author decided to portray the atomic bombings in such a “light-hearted” way? “Japan-kun, you’re out of control!! Take this, ATOMIC PUNCH HYAA!!!” “Itaaaaai, America-kun hidoi yo!!!!” No of course not, because making light of a literal war crime where their are survivors still to this day is fucking disgusting! But apparently it’s totally fine to do that to countries that Japan actually colonized!
It’s literally Japanese nationalist propaganda that excuses imperialism as a fun joke. And the brunt of the people speaking out about this have been Korean, Jewish, and Black people - including Afro-Latinos who were still called gringos for disliking Hetalia despite being Latino!
This literally isn’t even covering how countries like America, Canada, and Australia are portrayed as white people which is Indigenous erasure. Or how the author has a chronic problem of anthropomorphizing majority Black countries with super light skin. Or how anthropomorphizing NAZI GERMANY in itself is a terrible premise!
There have literally been academic papers written in Korean about how revisionist Hetalia is so if you’re under the false assumption that it’s only US Americans “complaining about made-up SJW issues”, you’re wrong and I can happily link you to Korean twitter threads written in Korean by Koreans living in Korea that are discussing all the problems with Hetalia.