Who is translating...
Who’s translating all of the Esperanto Wikipedia articles?
It is a wiki so there is a lot going on. The same guy who started the duolingo course in Esperanto started the esperanto wikipedia... Any one of a few hundred wiki loving expert speakers write directly or translate things they think are important and newer speakers dip ,thier toe in the water when they feel competent. Esperanto speakers are comparativley few in number but tend to be both technically competent and very enthusiastic ( which is why vikipedeo is the ninth or tenth largest non english language wikipedia)
Why do you think they are translated? Many are written directly in Esperanto.