Americans have always generally glorified Europe, had a sort of mystified view of it, rose-tinted glasses, Europe is thsi splendid place with luxury and class and elegance
Then every retard in the world got a smartphone and sits on instareels, twitter, tiktok.
Here, Americans, who long saw europeans as cool and interesting now have to listen to constant "HAHAHA AMERICANS ARE SO FUCKING STUPID AND FAT WE FUCKING HATE YOU!" from people who've never even stepped foot here, and if they did it was probably some shithole part of LA or NYC for a 1 week vacation, and they just base everything on some exaggerated image of what actually only exists in flyover shitholes, trailer parks, and innercity areas.
Most of the people shitting on America have no clue what it's like to live in a nice town in the north (northeast minnesota, small wisconsin towns for example) or a cozy little hamlet in new england, or a decent small city on the east coast, and they have this warped idea that every single american is a mobility scooter riding fat retard who can't find brazil on a map. that IS true for like 30-40% of americans but a lot of people here are generally sociable and well educated. So to then get shit on by countries you admired, you feel spite and animosity. Speaking from experience here. I used to think Europe was fucking awesome and really wanted to meet europeans and learn different languages until they all laugh in your face for nothing despite being polite and softspoken and genuinely curious about their cultures, just because you have a retard president and your country has fastfood.
tl;dr americans hate others because others hate americans. it's a defense mechanism.