Musical muck I am disgusted and sickened by the new musical about the cowardly murderer, Luigi Mangione, coming to New York City this summer ( “Staging Villain ‘Luigi,’ ” March 4). The people who have created this trash are as depraved and unhinged as Mangione. He’s a gutless, cowardly, back-shooter who killed a decent human being. Mangione should not be celebrated but denounced and condemned for his killing of Brian Thompson. I will boycott this trash and I ask all intelligent people to do the