Tf2 medic hates the word "über" because it destroys his indigenous identity.
The "ubercharge" original word was "koimoi pioba" which means "the healing steam" in the extinct poipoi bavarian language.
The Austrian government changed it to "übercharge" to fit their vocabulary well, also because they hate medic's indigenous poipoi bavarian and kikonian cultures and languages.
Medic wanted the Austrian government to stop changing his indigenous poipoi bavarian and kikonian languages and turn them to their fictional stolen language that they call "german" but it truly isn't even close to real german at all, it's a combination of nordic, slavic, and celtic languages into gibberish, but they disagreed by putting bugs in his voice synthesizer, the only way he can "talk" to his husband despite being mute.
He also hates the "schadenfraude" not only because it's an Austrian word, but also because he was literally bullied, abused, mocked by, and nearly killed because of this. He faked his smile and pretended to laugh using his voice synthesizer despite the fact that he actually about to cry because he feels bad for that suffering person, medic wants to heal and revive that person because he's motherly and gentle.
Medic doesn't actually want to laugh about a suffering person, instead he wants to support that suffering person and take care of him. Because medic knows how it feels to be mocked, harrased, abused, and bullied by people for no reason, medic knows the sadness, trauma, and even fear from it...
Medic didn't actually typed "can you feel the schadenfraude", and a lot of insulting stuff, it was typed by the Austrian government to make medic look like a "terrible person" even though medic doesn't want to do this.
Medic doesn't want to fight, he just wants his ancestors back....
He also don't have an accent because he's mute, what were you expecting from a mute person.
Also, in the mvm trailer, the blu medic literally whispered to archimedes (because he's mute) "polai ne hino kuku" which means "goodbye my little dove" in poipoi bavarian language. That scene made me emotional as fuck!!