“When Beatrix Ruf abruptly stepped down as artistic director of the Stedelijk Museum Amsterdam three weeks ago under a cloud of suspicion, the art world reacted with shock and disappointment. … In her first interview since resigning, Ms. Ruf told The New York Times by email that the private consulting work at the center of the accusations against her had been approved by the museum’s board, and that claims of a conflict of interest were baseless.”