Traditionalist offshoots are interesting as anthropological studies, but they exist in many religions. The numbers are more substantial than other religious splinter groups probably a reflection of the relatively recent reforming of the LDS church. I agree that the FLDS child bride practices are reprehensible.
Yes, child brides are disgusting but that is what Joseph Smith practiced and so do the flds.
The flds are not an off shoot, the SLC lds are (I think from the SLC lds there are about 150 off shoots - not sure about the number).
Other than that, I am not sure what your point is here.