They are now.
But they were widely despised and persecuted throughout much of the 19th Century. Their towns were burned down. They have held on to their scripture(s) and basic theology, but have fashioned themselves in the mold of a conservative Christian church.
For example, I think Mormons fight so hard against same-sex marriage because they don't want anyone to remember their former support of polygamy and think they are back-sliding on "traditional marriage" or "family values".