How is it anticompetitive to stop sharing data you own with another business who has taken a more competitive stance against you? It’s not like Facebook is a public service that everyone is entitled to. And I say that as someone who deleted his own account long ago. I dislike Facebook for a lot of reasons but this isn’t one of them.
It is retaliation for another business competing with you. That is literally using your market power to try to reduce competition.
But taking anti-competitive actions by itself isn't necessarily an issue, but it is a problem if you're deemed to have significant market power in a defined market.
Essentially: if Facebook is deemed to have significant market power, this could be a problem, if it doesn't have, then it isn't a problem.
Anti-trust relies heavily on the precise definition of a market (which is a subject that Hacker News comments generally ignore when crying wolf, I mean, monopoly).
I don't think its anti-competitive considering they don't need to provide any third party APIs at all. Plus it's not like to create a social app you absolutely need FB login or FB data. I think if your company can't make it and you're blaming FB for not giving you enough data maybe your business model was a little too dependent on Facebook in the first place.
