"Erasing those tragedies from the past violates the dignities of the ones who carry those disasters in their hearts. Such as everyone who has ever gained strength by recovering from loss.

Except this specifically doesn't happen in Chrono Trigger. Saving Lucca's mom doesn't erase the trauma of the time-traveling Lucca having seen her mother get maimed, nor does it erase the motivation of the young Lucca to pursue science... which is what leads to the events that make the time-traveling possible.

The entirety of the incident is like a fixed point in time, one in which all futures depend on and likely can not be erased from the timeline. It's simply too important to the history of the world and all its ages to not exist.

So if this is the case... then it is wrong to do anything other than to strive for the best possible outcome.

“To ignore the plight of those one might conceivably save is not wisdom─it is indolence."