You can't square access to "aggregate sales data" of inventories that are not yours with having a policy not to use third-party sellers info for personal/internal sales gains. In this case Amazon went from being a decent host and service provider to a malicious, unfair competitor.

Either they divest themselves from being an active participant in their marketplace, or they put out their eyes and sequester Third-Party sales and transaction records into a bin to never get looked at except for reports to third-party sellers themselves. That's about the only way I can see for Amazon to ethically move forward.