In this article TWTR Follow your favorite stocks CREATE FREE ACCOUNT The Twitter profile page belonging to Elon Musk is seen on an Apple iPhone mobile phone. Nurphoto | Nurphoto | Getty Images When Elon Musk said last week that Twitter has experienced a "massive drop in revenue" under his recent tutelage, he blamed the decline on "activist groups pressuring advertisers." There was some merit to his claim. A group of civil rights leaders had sent a letter to the CEOs of major companies, including Anheuser-Busch, Apple, Coca-Cola and Disney, urging them to relay their concerns about brand safety on…