"openly challenging the pope to clarify parts of Amoris Laetitia that they find to be a source of confusion"

They are "openly challenging" the Pope to clarify parts of Amoris Laetitia because the Pope refused to respond to their private request.  
The Pope is infallible on theology and dogma, apparently not so in manners and respect.
If the shepherds of his flock are confused, then the likely assumption is that at least some of the herd are too.  Or more likely, the Pope is not used to be challenged because he is surrounded by sycophants and lives in a bubble.