The England colonies because of theor religeous beliefs
The Kansas-Nebraska Act was passed by the U.S. Congress on May 30, 1854. It allowed people in the territories of Kansas and Nebraska to decide for themselves whether or not to allow slavery within their borders. The Act served to repeal the Missouri Compromise of 1820 which prohibited slavery north of latitude 36°30´.
I remember learning that this is because of the unintelligent. It is because they want this to be directed to people who need to know what they are doing.