It is thought that it was because Kiri-mon had been often handed over to followers of Shogun-ke (family positioned to accede to the shogunate) since the Muromachi Period and some families had used it as Kamon, which Meiji Government considered against.
室町から続く将軍家の家来に対する桐紋の譲渡が頻繁にあり、家の家紋として使用しているものもいたため、それを配慮したためだと考えられている。