I think the ToS is lenient enough to get away with most things.

I suspect that its a two-fer,

1) zuckerberg has said "it must be done" as part of the AI push

1.1) it might be also that Wang has pushed to get that data, but thats a guess. I doubt he has that kind of sway

2) they've realised that the FTC isn't either capable, or they have bribed the right part of the government to avoid getting nailed.

The thing that gets me is the number of lawyers that are there, and the sheer amount of process that is there to stop this kind of thing happening requires Zuck to explicitly say "I WANT THIS" repeatedly.