I'm not sure if the legend is true or not. But this argument doesn't really disprove it. The devices don't need to send full audio recordings. They are powerful enough these days that they can do a cheap on-device audio analysis and tagging, and then upload the (very small) tags. It doesn't need to be Siri quality analysis because it doesn't matter if the analysis is incomplete or sometimes inaccurate. They would just be scanning for certain keywords.
As for whistleblowing... Is there really that much to whistleblow about it? We already know that ad-based companies like Google are collecting our data every chance they get, because they make billions of dollars from it. They're scraping our emails, studying our GPS location, paying attention to who we are in proximity with, etc. The level of surveillance is incredible and people don't really care. It wouldn't be headline news to find out that they are taking advantage of yet another side channel.
As for whistleblowing... Is there really that much to whistleblow about it? We already know that ad-based companies like Google are collecting our data every chance they get, because they make billions of dollars from it. They're scraping our emails, studying our GPS location, paying attention to who we are in proximity with, etc. The level of surveillance is incredible and people don't really care. It wouldn't be headline news to find out that they are taking advantage of yet another side channel.