No true seeker of truth can oppose the fully free marketplace of ideas. For details of the hardheaded practical case, you can do no better than to consult chapter 2 of John Stuart Mill’s On Liberty. If you can’t spare the time to read this short chapter and book, here’s the money quote: “He who knows only his own side of the case, knows little of that.”
Horton Debates Mossad Chief
Seriously. Piers Morgan had me on with John Kiriakou, The Dersh and Danny Yatom, the former head of Israeli intelligence. https://www.youtube.com/watch?v=uwCTktxy0ho