The humor here is that the woman in the photo is Stephanie Renee Guttormson. She's an atheist and current president of the Richard Dawkins Foundation for Reason and Science. A few years back she posted this picture of herself, and one of her friends waggishly captioned it "Hey Kids, Let's Talk About Jesus" and the God Warrior Wendy meme was born.
https://www.facebook.com/pg/ThinkStephtically/
