The new law barred courts from restricting the custody of a parent who is competent, protective and not abusive solely to improve a relationship with the other parent. It prohibits reunification treatment that is predicated on cutting off the relationship between a child and a protective parent the child has a bond with.
Putting aside the insanity of this ever being allowed, it doesn’t apply in this case because custody has not been (officially) cut off. She’s in jail because she objects to the therapist and her methods, believing them to cause severe anxiety in her children, and has thus tried to interfere with the court ordered sessions.