Greg Mankiw wrote a response to his students, who protested his teaching, in his last New York Times column. He basically blames the students for not knowing enough economics. He goes on to say that the complaints of the Occupy Wall Street (OWS) movement, in support of which the students had boycotted his class, are also a “grab bag of anti-establishment platitudes without much hard-headed analysis or clear policy prescriptions.”
He also suggested that students boycotted the wrong class, since his lecture that day was on inequality. Note that his views on inequality are strictly based on conventional mainstream neoclassical theory. Inequality for him is based on education (see here his critique of Krugman’s views on inequality). So basically the top 1% are more educated, more productive and, as a result, receive more. You cannot protest market forces.
Income distribution, according to neoclassical theory, is determined by the relative productivity of the factors of production. If wages are stagnant it must result from the fact that labor productivity is also sluggish. However, the evidence for that is thin at best. As it is well known, labor productivity has increased over the last 30 years in the US, while real wages have not budged.