In judging Cardinal Burke's past actions, Cardinals didn't have the right to question JPII or EPBenedict...especially Benedict.  This is why I find his continual opposition to Francis humorous.  Ironically, these four cardinals are engaged in using personal discernment in how they approach the teachings of a given pope.  In this particular case they are using their power of discernment  in order to deny the validity of the same use of discernment by laity and lesser clergy.  In the end, it's about protecting their own power and status in the Church and nothing does that better than insisting on rigid application of Church teaching.