Why does it matter if it's Americans listening to it vs third world contractors?

Also Google and Amazon are a large American companies that mostly try to do the right thing in terms of user privacy. I'd be more concerned about the random IoT microwaves and fridges made by a small company in China or Japan with their own assistant features built in sending audio to god knows where. Atleast I can reasonably trust the wakeword implementations for Alexa and Home, you can't even trust than with other h/w.

It again comes back to, yes, researchers listen to a carefully chosen random selection of audio clips and they're not really targeting a single user. It's impossible to explain that nuance in marketing material.