There's no reason for him to make a dog whistle reference to The Bell Curve. Even though people don't agree with or like that book, it's not exactly a book that

There's no reason for him to make a dog whistle reference to The Bell Curve. Even though people don't agree with or like that book, it's not exactly a book that is so scandalous and horrific that you need to dog whistle about it. If you're going to dog whistle, it's going to be to something so horrific it can't even be discussed with any pretense of academic distance or distinction. The problem with the "dog whistle theory" though is that only dogs can hear them, so anybody who is not a dog can label anything to be a dog whistle with no real proof whatsoever.