The title of Mankiw’s post is “Do two rights make a wrong?”, not “do two wrongs make a right” as in the HN title. Mankiw argues that it is noble and “right” to

The title of Mankiw’s post is “Do two rights make a wrong?”, not “do two wrongs make a right” as in the HN title. Mankiw argues that it is noble and “right” to voluntarily give someone a kidney. Likewise it’s noble and “right” to voluntarily give someone money to help them pay their mortgage.