While we’re at it, why doesn’t the Church just tell each of us personally whether we’re going to heaven or hell when we (or our parents on our behalf) ask for baptism, save everyone time and effort by refusing to baptise those who are hellbound anyway, and be done with it! After all, God knows who will be saved, and He gives the Church the fullness of truth pertaining to salvation, right?
There are things God chooses not to reveal to the Church or to us. This is so that we will all remain ever vigilant in regards to our souls, ever striving to be holy, ever preparing as best we can be to meet Him.
This gives greater glory to Him and allows US to gain more merits and graces than would, for example, just telling us the hour of our death and letting us slack off for our entire lives (minus an hour or two for a quick visit from the priest for confession and last rites).
Well, the very best way to prepare is the sacraments, including sacramental confession. So it stands to reason that God, knowing that confession is the very best thing for our souls, would want as many of us as possible to make the fullest possible use of it.
So he chooses not to discourage us from it by telling us too many ways around it. Rather like a parent who wants their child to study hard, because it’s the best road to success, doesn’t fill their heads with stories of high school dropouts who did good (because most don’t, right?)