Blaming the user for the lack of simple coordination between devices when they buy into your ecosystem across multiple devices and attempt to use the advertised features doesn't seem like a great product strategy.
It's redundant and counterproductive to have multiple devices listening for the code phrase.
I imagine that if I put 10 iPhones on a desk and say "Hey Siri", that wouldn't work out too well. Doesn't mean we have to start "blaming" people, companies and things.
To the article’s point, Amazon’s has no problem Determining which should answer a question if they are all the same account piled on your desk.