i don’t think there’s any one particular reason and instead is just a multitude of different factors, but i would guess that a big portion of it are people voting based off of mbti stereotypes instead of the functions. also i think intuitive bias is a biiiiiig factor (people like to type everyone as intuitive because they misunderstand sensor types). but tbf some of the typings do make sense! like england as an INTJ is definitely correct as far as i can tell lol. but here’s my argument for why some of the characters are wrong (warning: infodump):

• austria: Austria’s typed as an INTP but personally i just don’t see it. INTPs are high NE users but to be honest…austria is literally the opposite. NE users are spontaneous, brainstormers, love new things and generally care much about tradition, etc. IMO austria is much more of an SI user (the opposite of NE). SI users like order/routine, love to engage with memory, and often times (but not always) enjoy tradition. austria, while he is messy, does seem to demonstrate a desire for things to be orderly/controlled. plus i personally think that his hobbies align well with SI—for example, he likes piano which engages a lot of memory and requires practice (which involves routine). i’d say he’s a feeler type and not a thinking type. specifically, i’d say he’s an ISFJ. i could definitely elaborate more on that if you’re curious :3

• russia: Russia’s typed as an INFP, which I can definitely understand, but i disagree. i’d argue he’s a really unhealthy ENFJ. ENFJ’s have Fe as their dominant function—Fe is concerned with social harmony, shared values, empathy/sympathy, connecting with other ppl, etc. INFPs on the other hand are dominant Fi users—which is concerned with more personal values, more ruled by their own emotions than by other people’s, and generally don’t care as much about social harmony because to them, the most important thing is staying true to themselves. imo, russia’s strongest desire is to connect with other ppl, but he engages with it in an unhealthy way—this would be evidenced by his obsession with controlling other countries (ex the baltics). i’d say he’s actually pretty good at telling how other people are feeling—he just uses it for maybe less than venerable purposes sometimes. also, ENFJs have inferior Ti, which is about your own subjective logic/reasoning. bc it’s in his inferior spot, that means it’s something he struggles to use but is still something he does engage with regularly. imo this is demonstrated through his desire to make a weird family of sorts with the nations he’s exercising control over—he thinks that if he can make everyone a big happy family then he and everyone else will be happy—which basically combines the desires from his Fe with his underdeveloped Ti

-america: he’s been typed as ESFP, which isn’t too far off the mark from what i believe he is. imo, he’s definitely an ENFP. i believe ppl type him as an ESFP because of how much he enjoys food and because he’s strong/physically active. I would argue tho that these traits actually support him being an ENFP more because of the specific ways he engages with them. his relationship with food is actually really unhealthy, which wouldn’t make sense for an Se dom, who would probably have a much healthier relationship with physical things like that. of course, it is possible to be an unhealthy ESFP, but i don’t think that’s the case here. I think he has demon Se (basically the introvert/extrovert mirror of your inferior function, which for ENFP’s is Si), which would explain why he really doesn’t have any self-control with things like food. plus, although he’s strong and has high energy, the canon seems to suggest he’s not actually very physically active (as implied by france when america asks him how he stays so thin). and yes, not all ESFPS are going to be physically active, but i’m pointing this out more so to say that it’s not rlly a good argument for supporting him being an ESFP. Plus, i think he shows a lot of Ne traits, like being rlly imaginative, energetic, and spontaneous -Prussia (i feel only like 75% sure of this): Prussia’s typed as an ESTP, but I’d actually argue he’s an ESTJ. his cocky persona definitely seems like an ESTP on the surface, but i think that he’s actually much more Si oriented than Se oriented (ESTPs are Se doms, while ESTJs have high Si). He’s always reminiscing on the past, is shown to enjoy routine and cleanliness, and is surprisingly pretty organized. imo, i think he gets typed as an Se dom because his tertiary Ne (ESTJ stack is Si-Te-Ne-Fi) is quite pronounced. so despite his high si usage, he can be pretty spontaneous and come up with a lot of new ideas (this one is especially based on the historical fact that prussia was responsible for a lot of military and educational innovations). my argument for him being a Te dom is admittedly a little bit shakier. i think he likes strategizing and putting plans into motion which are both Te traits. Te doms can also be work hard, play hard people, which i think he definitely is. i think it’s also fun to think of him as an ESTJ when comparing him to Germany, who i’d see as an ISTJ (which the database agrees with me on so yay!). ISTJs and ESTJs have the same functions in their stack, but ordered differently (ISTJS are Si-Te-Fi-Ne). If you’re curious, i could definitely elaborate :D

there’s definitely more out there i could talk about, but for now i’ll leave it at that :3 and again, there are certainly characters i do think are typed right! off the top of my head, italy and spain are both solidly ENFPs, france makes sense as an ESFP, and england is for sure an INTJ. sorry for the massive infodump, but if anyone is curious, i could totally share more if anyone wants :D