"The committee suggested there was a distinction between Japanese and German and Italian aliens,

on the ground the latter two are 'thoroughly americanized' and 'as a group are loyal to the American war effort.'" (source)

The government didn't have the guts to admit that the internment of the Japanese was a response to pressure from the public. They claimed the Japanese Americans were unamericanized, however some of these people had resided in the U.S. much longer than their Italian and German counterparts.