text: "isn't people telling lies a reason to re-think the Church's teaching on truth-telling"
  
  You are exactly right.  Clearly, the bishops' systematic lying during the abuse cover-up tells us that the "Church's teaching on truth-telling" is very much a "Do as I say, not as I do" proposition, and is to be understood as such. 
  This, of course, raises the obvious question of how may other Church teachings are "Do as I say, not as I do" propositions.  If only Alexander VI were still around, he could probably tell us.  That seemed to be one of his areas of theological and canonical expertise.