Well, that's BS. I had a BT headset in like 2006 that would let you set the activation word to be anything. Admittedly, it only had about a 40% success rate at recognizing the word.
It wouldn't surprise me if it's an ML model that they trained on a billion pronunciations of the limited set of names or some shit coupled with them being phonetically distinct enough that there's even less room for false positives or negatives.