I think that’s an over-generalization. The very conservative abbey where I attend Mass does not use the very often. First of all, never on Sundays, because there are numerous visitors whose faith practice, to be polite, is shaky at best and are thus unlikely to have it memorized. But also, because the monks say the Confiteor every single day at Compline and the conventual Mass is geared to the needs of the monastic community, not the laity. So only hear the Confiteor occasionally at weekday Mass.
They use the formula that includes “we have sinned against you” (sorry I only know it in French). That certainly isn’t avoiding the fact that we are sinners. Occasionally at weekday Mass they use the third formula (trope).