I agree with Robert Cartaino that SE-Conlang is not a translation service. And while I agree with Adarain et al that, in general, translation questions ought to be off topic more than I disagree with the statement, I do think we need to retain some flexibility in regards to this kind of question.
The Toki Pona question referenced is a good example: it's not a pure "how do you say X" question, because the answer can not be "look it up in the dictionary". Rather this question, as I see it, delves more into how the language functions and the design parameters of the glossopoet.
The Black Speech question is also a good example because, well, there isn't a dictionary to look it up in. Also, online one can find many "reconstructions" and "cinematic additions" --- quasi-canonical, fan-generated languages and so forth for all the popular franchises. I think our expertise in the field as regards understanding & intuiting what might best be considered canon and what might best be called "fanciful additions to the canon" is well suited to this kind of question.
As for well settled, well known "standard" invented languages like Esperanto or LFN or Brithenig or Wenedyk (any language with an actual published dictionary or an accessible✳ online resource), sure we should be free to say "go look it up in the dictionary!" or "send an email to the author" and downvote or boycott or whatever we feel needful.
NOTE: webpages, especially older ones, have a tendency to disappear. If someone comes asking for help with a relatively well known invented language the online resource of which is now gone or hidden in some archive, I think it would be appropriate to a) give the immediate answer and b) point the seeker in the direction of said archive if there is one.