I don't think your extension in necessarily doing anything underhanded today, but I do think the privacy threat model marketed by your company is idiotic. You sell people fear, the idea that some corporation has binders full of GUIDs, and they know you bought socks! They are tracking you! Fear!
Then you sell them the idea that by installing your highly privileged software, that can read and transmit literally any data available to the user, they are enhancing their privacy. This is a stupid trade that nobody would take if they stopped and thought about it. The nebulous tracking thing is clearly lower risk than your browser extension, and there are other, better, less risky ways to subvert web tracking.
Then you sell them the idea that by installing your highly privileged software, that can read and transmit literally any data available to the user, they are enhancing their privacy. This is a stupid trade that nobody would take if they stopped and thought about it. The nebulous tracking thing is clearly lower risk than your browser extension, and there are other, better, less risky ways to subvert web tracking.