"Do the best you can until you know better. Then when you know better, do better."- this is how I feel about this quote from Maya Angelou-This quote is about grace for your past and responsibility for your growth. It says you are not expected to be perfect, but you are expected to change once you learn better.
Its a clear moral responsibility: once new insight, truth, or understanding comes, you are called to change your behavior to match that new knowledge.