Why Do Liberals Hate Recreations of Margaret Sanger Speaking to the Ku Klux Klan?

It is a historical fact that Margaret Sanger spoke at a cross burning Ku Klux Klan Rally. She even admits it in her autobiography:

"I accepted an invitation to talk to the women's branch of the Ku Klux Klan...I saw through the door dim figures parading with banners and illuminated crosses...I was escorted to the platform, was introduced, and began to speak...In the end, through simple illustrations I believed I had accomplished my purpose. A dozen invitations to speak to similar groups were proffered." (Margaret Sanger: An Autobiography, P.366)

So why do liberals hate when this event is recreated artistically?

This year's contest starts in late September and this year we have been promised a video from some very bright and creative students. Should be fun!