Anthony Tommasini is “flabbergasted by the decision of the Royal Opera at Covent Garden in London to drop the soprano Deborah Voigt from a new production of Strauss’s ‘Ariadne auf Naxos’ in June because she was deemed too heavy for a slinky black dress that is central to the director’s concept of the role. The company’s move is so appalling that you have to wonder whether there is more to the story.”