This title is actually a quote from the book -The Lone ranger and Tonto Fist Fight in Heaven
Sherman Alexie, the author, is implying, I think, that all of us have the choice to forgive (understand, accept, etc) our elders or not.
We may or may not choose to grasp their perspective and their version of the world when we are young. What Alexie may be saying is that we can wait until we are much older (when our parents are likely dead and gone) but if we do we will left with two burdens. The burden of seeing what it is like to have children of our own who dispute our values and the regret, when we finally see virtue in our parents' opinion but are unable to tell them so directly. This quote, and the story, is about balancing independent thought and the regret of words unspoken. A profound story.