Well, that's rather blunt, but quite true. I sincerely believe that somehow, someway, somewhere, we signed up to be here at this tumultuous time in history. There are no accidents or coincidences. We live in an orderly Universe, whether or not that appears to be the case. Those of us alive now are the ones to lead humanity into a kinder, gentler, more planet-friendly way of living.
So much for the "global" scale. The Whitman quote applies to each individual life, too. Life here on magnificent planet Earth depends on cause and effect, choice and consequence. So the choices we have made must lead to the days that are happening to us. If we don't like "the days," the logical remedy would be to change the choices made, choices of thought, word and deed. One of the toughest things in parenting is allowing a child to experience the consequences of negative actions. Preventing that is a huge disservice to the development of the child, because then they fail to learn the "choice and consequence" lesson, leading to frustration, confusion, resentment and inability to cope with "the days that must happen."
On the bright side, maintaining an attitude of faith, hope and gratitude tends to lead to good days happening to us. We can most likely look at friends or relatives and see the Whitman quote playing out. My mother believed in her illnesses and victimhood, and died a painful cancer death at age 61. My father was the eternal optimist and lived a mostly good life just shy of age 83. We may not like the way the cause/effect law plays out, but at least we have individual choice of how to use it.
Best of all, humans are resilient. These "days that must happen" will pass, and human consciousness will expand as a result. Good news!