Maybe as follows: Moshe tells the Jews "מה ה' שואל מעמך" - What does Hashem ask of you?? Just to fear Him!! The gemara asks "Is fear is small matter" that Moshe Rabbeinu says "What is the big deal?!" The gemara answers that for Moshe fearing Hashem was really no big deal.
That is very nice - but he was talking to Klal Yisrael and for us fearing Hashem IS a big deal??
There are many answers to this question. One is that the gemara is saying that if we cling to Moshe [and other tzadikim] then it will be no big deal. On our own it is very hard - but not if we are close to Moshe.
Maybe the same rule applies here. We put the broken luchos in the Aron to connect to Moshe Rabbeinu who didn't sin and then we can come to a point here we are no longer sinful ourselves.
