When asked about the reasons for these drastic changes, she 'pleaded/pled ignorance'. [=she said that she did not know the reasons]
Their decisions were made 'in ignorance of' [='without knowing'] the true nature of the situation.
His racist attitudes were born out of 'ignorance'.
(..) I have nothing but pity in my heart... for the chiefwitness for the State. She is the victim... ofcruel poverty and ignorance. But my pity... does not extend so far... as to her putting a man's life at stake... which she has done in an effort (..)1962 To Kill a Mockingbird