His surname however is german (probably of jewish origin) - translates to (literally) "bun-white"
In case you were wondering: In 1997, the World Health Organization ranked Hungary 66th out of 190 countries in overall health care system performance, behind Austria, Slovenia, and Croatia, but ahead of Ukraine and Romania. (Also ahead of FR Yugoslavia, which still existed back then. As far as I can tell, they haven't done a new ranking since.)
Couldn't this also just be "Hungarian doctors" (a general statement about them)?
No, because of "a". If I'd say Magyar orvosok voltak ott > then you could say Hungarian doctors were there. But in this case there is "a magyar orvosok" so you need "the".
Because one of the adjectives is attributive (it stands before the noun) and one is predicative (it says something about the subject, the Y in an "X is Y" template).
Attributive adjectives do not get number or case endings (unless they stand alone, without a noun, as in magasok "tall ones"), while predicative ones do.
(Oddly enough, German adjectives work exactly the opposite way.)
He was a Hungarian mathematician, but I think there are (and were) very good Hungarian doctors so Duo is wrong. :)
Ez egy buta mondat. Sajnos, aki ezt a mondatot ide tette nem igazán tudja mit beszél! Egy külföldi ez alapján mit gondol? Nem vagyok orvos.
Shouldn't the English translation be "THE Hungarian.....", given that the corresponding Hungarian sentence is "A magyar.."? Omitting the The in the English sentence significantly changes the meaning.
"Medic" is not exactly the word you are looking for here, as it is a general term referring to various people, with varying degrees of training, involved in the medical professionals. "Physician" is the precise word for this sentence.
Are Hungarian physicians "not good'? In fact they are amongst the finest in the world.
When I lived in Budapest, I was impressed with the quality of the doctors there. Fast, efficient, knowledgeable and nicely down to earth.