Our organist never cuts loose with Louis Vierne until the postlude . . . although if he played him up front, nobody could talk before Mass because they couldn't hear themselves think (which would kind of make it pointless because they couldn't hear themselves pray, either.)
Given the penchant of so many parishioners to indulge in idle chatter before liturgy, a quiet Bach fugue might actually serve to quiet them. Perhaps this desire to have background music is a reflection of a world now filled with inescapable noise. People are no longer accustomed to silence and immediately respond by filling it with music or conversation.