Just a guess but might be because it doesn’t technically cause the watch to not work (and to be totally fair….buried in the terms and conditions there is a disclosure that does not guarantee that all features will be available in all areas nor are we guaranteed that any features you do have will continue to work in the future. It’s a standard scapegoat that many products terms will use but it’s there). The feature is turned off but the sensor is still there from my understanding.
But there have been sales at many authorized retailers before and after the ban. Some of those retailers are also still selling the versions that does still have the feature active (Best Buy is an example that has had the watches on sale for $70 off which may still be going on. Last week they had them on sale for $100 off during a 24 hr flash sale. I can verify that a friend just purchased and received one that did not have the parts number ending in LW/A and does have the feature. How long this remains to be the case is unknown but it’s likely these retailers still have inventory imported prior to the ban). At any rate….its unknown if the ones that Apple currently sells will never be able to have the feature activated once an agreement or resolution to the lawsuit is reached….honestly no one will know officially until that time comes and Apple says so.