You're right, it's not Facebook's business, but this 17-year old and her mother chose to discuss a crime on Facebook's platform. Facebook had a legal obligation to hand over those messages because they were served a valid warrant.
She aborted at 28 weeks. That's nearly 6 and a half months pregnant. Most babies can survive outside the womb when they're around 22 to 23 weeks. This was a baby, not some tiny fetus.
Done. My apologies.