Reading this article it shows you that sympathy was a very narrow thing. The New York Times talking about what to do with Polygamy had this to say:
The mere suggestion of a conservative course in this business throws the radical anti-Mormons into spasms of indignation. They declare the time has come for the extirpation of the evil, and that the work must be accomplished forthwith, even if it requires the entire military force of the United States to do it. Men who do not favor the fire-and-sword policy are denounced as “Jack-Mormons,” secretly favoring polygamy.