gidget7 you are absolutely correct- they should have taken all the men first. Maybe that will be the next step and move the lovely women and children back to their home.
It would seem to make more sense, at first blush, to take the men off the ranch and leave the women and children. However, they have no right to arrest all the men without fist having grounds for arrest. They simply don’t have that. (Some of the men may not even be married.)
Apparently, they believe they have more legal grounds to protect the children, thus allowing for an order of temporary custody. At least they can point to the number of girls, who appear to be under the age of consent. Once they identify who impregnated these girls. Then they would have the right to remove those men from the ranch.
Having said that, I’m also upset they removed the mothers. It should have been enough to cut off their communication with the men to protect witness tampering.