These remarks were given by philosopher Johann Frick (now at Berkeley) at a Princeton conference in honor of Peter Singer, and make some interesting points.  For example:

Peter has been an avowed utilitarian for most of his career, and his commitment to utilitarianism no doubt played a major role in leading him to adopt many of the ethical stances for which he is known.

And yet, it is rare that you will find Peter, in his published work, making arguments of the form: “You should believe p, because p is entailed by utilitarianism, and utilitarianism is true”.

Much more commonly, you will find him skillfully appealing to mid-level principles that he expects will command the assent of people with widely divergent ethical outlooks. This genius for making his arguments as ‘ecumenical’ as possible is one of the major reasons for Peter’s success as a public intellectual.

This seems right, although it seems an incomplete account of his success as a public intellectual (surely he has been the perfect public moralist for the neoliberal era?).  Professor Frick also makes some interesting observations about Singer's "esotericism" as a public moralist.  I am not a fan of Singer's philosophical work, but I found this short essay quite interesting and illuminating.