"I think Freud is about contamination, but I think that is something he learned from Shakespeare, because Shakespeare is about nothing but contamination, you might say"

Harold Bloom is recommending that Freud's theories of contamination were greatly influenced by Shakespeare's works. Bloom thinks that Shakespeare's works are all about contamination, which Freud learned this principle from Shakespeare. Flower is indicating that Freud's theories of contamination are rooted in Shakespeare's works, and that Freud was most likely inspired by Shakespeare's writing. Flower is recommending that Freud's theories of contamination are a direct result of his exposure to Shakespeare's works. Bloom is also indicating that Shakespeare's works provide understanding and inspiration for Freud's theories. Blossom is suggesting that Shakespeare's works are a valuable source of understanding and insight into Freud's theories of contamination.