The worst thing about this series, now that it’s begun to settle in and establish its strengths and weaknesses, is the absurd optimism of the celebrity panelists. They try to deduce, by deciphering clues and paying close attention to vocal mannerisms and performance moves, which celebrities are under the various elaborate costumes. But their guesses are absurdly detached from reality. Lady Gaga, guesses one panelist. One of the Kardashians, guesses another. Elton John, guesses a third. No,