ST PETERSBURG, Russia (Reuters) – A group of Russian anti-gay activists sued American pop star Madonna for $10 million on Friday, saying she had insulted their feelings when she spoke out for gay rights at a concert in St Petersburg last week. Performing in black lingerie with the words "No Fear" scrawled on her back, Madonna attacked a city law adopted in March that imposed fines for spreading homosexual "propaganda". She had earlier called the law a "ridiculous atrocity". …