You're right it definitely doesn't fit neatly under any current anti-trust laws. I think the justification for why something like exclusive dealing agreements

You're right it definitely doesn't fit neatly under any current anti-trust laws. I think the justification for why something like exclusive dealing agreements in monopolistic conditions is unfair could definitely be applied to why being a competitor in your own marketplace, while leveraging your customer's data, and boosting your own listings could be deemed unfair and lead to monopolistic conditions too.