John Edwards made some mistakes. Do any of us believe that when he runs for office again (and he’s planning to) he will have learned anything? Advocation for treading lightly on flawed characters is contrary to wisdom.
“Pristine” candidates are a fantasy, but ones who, for example, have drug “mistakes” in their past and who see the solution as simply getting rid of the social and legal morés surrounding it aren’t actually admitting to do anything wrong - nor growing and learning.
They are simply looking to remove the obstacles that made their life more difficult in the past in hopes to alleviate themselves of stigma.
That is why “flawed” candidates remain.... flawed.