The differences I see in this case are:
1. Their official, published beliefs are that adolescent girls should have sex with whatever man they are told to have sex with.
2. There is a lot of physical evidence that they are acting on their beliefs (many pregnant teen girls).
3. There are many ex members of this cult who will testify that this indeed occurs regularly.
I can't put this in the same league as McMartin preschool. You are right. At this stage it's Waco Revisited - with the Initial Raid working as planned.
Iff'n only those dumb FLDS had gotten themselves a few guns, they would have a lot more support on FR.
The FLDS failed to follow through and keep the abandoned boys as a local heavily armed militia.
Still, there is no parallel with WACO. They were, as it turned out, manufacturing thermite grenades on site.