Are we expected to improve our translations by looking at other people's translations without acknowledging helpful translators in any way?
Yes and no. The goal is to practice a language, not to be perfect about it. The best way to improve is by taking lessons AND translating. Except if you're already good with a language, translating alone won't get you far.
Anyway, you won't be really fluent unless you communicate with people in that language, no matter how skillful you are with translating or with grammar and conjugation.
Personally I don't think we need professional translators to learn a new language.