@Roberta,
Roberta, I've been thinking about you response off and on for a long while.
How does one determine if something is really none of their business?
Is it looking at in the immediate short term? Is it to avoid doing something unpleasant at that moment, not wanting to get involved? Is it turning a blind eye to something that has no impact on you, or those immediately close to you, at that instant?
How far does a person look in the future, in the ripples caused by saying something is not my business?
Is it not someone's business if taking action does not mean something changes immediately?
Is is not your business because someone else told you it's not?