Of course the Harry Potter fandom is critical of JK Rowling these days. Her books taught a whole generation to hold powerful adults accountable for their actions; that complacency isn't progress; and that even beloved authority figures - like Dumbledore; like her - can screw up.
the American stuff isn't from the books; it's from the huge expanded wizarding history she put on her website. the dumbledore stuff was word of god: it's never in text, but she said it afterwards