Is there a reason to write "it"? The other sentences speak about "he" (a person).

The original sentence in Lojban in gender-neutral, and species neutral. It literally means 'The thing spoken of previously is sick'. That's why I translated it in such a fashion.

On the page http://tatoeba.org/epo/sentences/show/692876 I can see, that earlier sentences as the Esperanto sentence with the number 378508 and the Russian one with the number 675589 both speak about "he", a male human not about "it".
I suppose it is possible to precise in Lojban, that there is some wrong functioning in the body of a male Earth human being. So I am inclined to think that there is some inprecision in the Lojban sentence. Am I right?
(I beg pardon about my poor English)

Yes, although it is possible to be precise in Lojban to that point, I believe that the author chose to interpret the 'he' in the other language sentences as a reference to a prior-stated person, which cannot be expressed in most natural languages (I know that at least in Japanese, this is actually possible).
And don't worry about your English; it's fantastic.

"O, hasta."