The 'dubia' cardinals are not fulfilling their role as cardinals.  They are not 'front line' supporters of the pope.  This is the only reason for a cardinal's existence as a cardinal.  And this was the purpose of cardinals since before the Second Lateran Council.  These 'dubia' cardinals are too much into THEIR positions as temporal princes, rather than shedding it by working with the pope as SHEPHERDS.