Why not compensate players for in-game bugs?

After a recent talk with the support team, I have found out that if a player suffers a ranked loss due to an in-game bug (for example, the recent "Xerath's Q stops working" issue), that Riot is unable/unwilling to give back the LP lost. I understand that if someone just says "hey, ____ happened, gimme LP" that would not be fair, but if a review of the game log (necessary for discovering and fixing the bug in the first place) proves an issue happened, why are players given the shaft? This seems like a real oversight in policy.