Why does the United States prohibit Japanese from entering the country?

The Japanese government protested against the decree 1924 signed by the US legislature on May 26th, prohibiting Japanese from immigrating to the United States. The American Legion, the American Federation of Labor and other influential organizations summed up five reasons for excluding the Japanese: 1) The Japanese are difficult to assimilate and the cultural differences are too great. 2) Their birth rate is three times that of white Californians. Will make the white people there a minority. 3) They pose an economic threat. 4) Japanese workers can establish foreign colonies in the United States. 5) China and Koreans are excluded from Japan's territory, so Japan has no right to protest this exclusion from the United States. Japan recalled its ambassador to the United States, and a "hate America" demonstration broke out in China.