Cordially,
The putting of children into foster care was not related to the monogamy or not of couples. It was related to the evidence of abuse of children observed at the compound and the duplicity of the cult members in lying to the CPS.
Since they could not determine which child belonged to whom, they had no choice but to put them in foster care until their identities could be determined.
If the flds people don’t like that, they can remember that they brought it on themselves by playing games with investigators.