I don't get it. "He is not nice to me" means that he behaves in some impolite way towards me, right? But, shouldn't the phrase be translated as "I don't find him nice (handsome)"? (because this is my (superficial) understanding of this Polish phrase). If not, how do you say that in Polish? =)
Yes, it probably means that he's impolite - although technically 'not nice' can simply mean that he isn't nice = he's completely neutral. Or doesn't notice you at all.
No, that rather doesn't have this understanding in Polish, if it had, then it was rather lost at least a few decades ago. I think you could once say something like "On nie jest mi miłym", which would mean rather "I don't have feelings for him" than "I don't find him handsome". Very old-fashioned, anyway.
Translating literally the word "find" and your whole sentence (using 'handsome'), we have another old-fashioned possibility: Nie znajduję go przystojnym.
But today, I think I would say "Nie uważam że jest przystojny/żeby był przystojny" (the first one is simpler and probably a lot more common) = I don't consider him handsome, I don't think that he's handsome, sth like that.
it feels so unnatural to me (fluent german and english) to put the to me part not in the end, because i dont quite get it in my head how it makes a focus like it does in polish :)
on nie jest mily dla mnie would b the equivalent to " To me, he is not nice" (But to others) ?! whereas i interperet the sentence order of nie jest dla mnie mily as that. argh
Generally, I'd say that the last part of the sentence carries most focus, some people call it "new information". So here, the most important part is that he is not NICE. In your sentence, that he is not nice FOR ME.
Maybe the focus is not that strong as I made it sound, but it's definitely present.
The word order in Duolingo often looks strange to an English speaker, but reading your comments again here (you have made a similar point before) and looking at other comments, is this 'emphasis' something we do not notice because when we speak we stress different words (in sound) to shape their meaning?