Wild guess: It probably took 'Mir', meaning world, kingdom, etc. in Russian, and made a connection to "Mordor", or perhaps "Mordor" is even spelled as "Mirdor" in Russian.
In modern usage, Mir means world, not kingdom, and Mordor is not spelled Mirdor. Besides, that's not how Google's translation system works.
Mir can mean numerous things. And how is it not how Google Translate works? Do you have inside information? Because the only information we have is that it scours the web, makes connections, and forms a graph. Can feed it some "corrective" data as well.