There could be multiple factors I think, like: your language skill level, translation quality, "closeness" of languages, psychological predisposition towards your native language.

Depending on the form of the thing you are translating it can be simply impossible to translate properly (like poetry).

I'm currently reading English translation of "Black Obelisk" which I believe is written in German and it isn't any worse than Russian translation (my native language) to me.

In any case, what was originally asserted is that English is somehow worse than other languages as a "transitional" translation language for words or simple phrases, so I argued with that specific idea. Translating literary works is a subject of it's own and where the quality is much harder to measure.