Well, my reasoning was simple: if we drop a language, then the only solution for users is installing in English, right?
Think of a user who speaks some minority language well and a major language other than english reasonablly but thier knowlage of english is very poor/nonexistant. Such a user is much better off knowing that thier favorite language is not properly supported and able to select another one they know reasonablly well than ending up with an install mostly in thier favorite language but with a few key screens in english.