Complex sentence: While Geisel preferred to let his work speak for itself, in 1986 when the line first started being used by the pro-life movement, Geisel, who would speak out to protect his characters from exploitation, demanded a retraction and received one.
Split into simpler sentences: While Geisel preferred to let his work speak for itself, he did occasionally speak out to protect his characters from exploitation. In 1986 when the line was first used by the pro-life movement, he demanded a retraction and received one.