This latter view is advanced, remarkably enough, by a theologian Martin Rhonheimer from a university endorsed by the Pope. He is a professor at the Pontifical Santa Croce University in Rome and wrote an essay on this particular distinction in the Neue Zürcher Zeitung.
There was a thread last month which claimed that the "peaceful" side of Islam is the heretical side, comparing it to the Protestant Reformation breaking off from the Catholics.
I agree that peace is heretical to Islam. The comparison to the reformation, however,is just a cheap shot.