Hi Modulous
As a teacher I think that you are overstating the fact that we may be guilty of a vast institutionalized conspiracy. Surely in todays world you have to consider that we are learning many new things, which will always need to be updated, especially in the sciences. As to the 15th centaury, the only history book most people in Europe had was the bible, which was accepted as entirely true, as were a wide range of legends and folklore. Things have changed, and so has what we teach today.
Also I would take issue with your initial statement citing flaws in education. More correctly it should be flaws/ gaps in the knowlege that we teach, which we all strive to amend. In consequence we who teach, pass on knowledge which enables other more brilliant minds to expand the borders of human achievement and knowledge.
But to answer your question, no, how it can it discredit any discipline, as long as that discipline is willing to change along with what we learn.