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'.
(..) But the origin of this clock completely eludes me. I've never seen anything quite so beautiful that I know so little about. This is a pleasurable torment. My ignorance amuses me. "My ignorance amuses me." - My ignorance amuses me?! - Yes. I've always found your ignorance quite amusing. (..)2001 Lara Croft: Tomb Raider