I felt challenged as an environmentalist when I watched the 2014 Netflix documentary “Cowspiracy: The Sustainability Secret”. One of the experts from the film, Howard Lyman says, “You can’t be an environmentalist and eat animal products—period.”   Mr. Lyman came into the public eye on a 1996 taping of The Oprah Winfrey Show titled “Dangerous Food.” At that time, he was …