I don’t what are you talking about. Machine Learning is one the fundamental technical pilars of modern Facebook. It’s used in almost every process imaginable in some way or another.
If in doubt, users can tell by the no-recourse no-logic no-sense moderation activity.
I hope some day they apply it to Sponsored Ads, because their targeting is absolutely terrible.
I doubt it would have to be used that much, and results are questionable and even malicious at times. So, not sure if that makes people working at AI at Facebook that great...