That is absolutely incorrect. It is possible to change Siri interaction and name. My Siri answers to "Paslushe Olga" meaning "Listen Olga" instead of "hey Siri" which is for barn dogs and *****.
even in English UK which I prefer to American.
1. > System Preferences.
2. 4th tier from top: Accessability.
3. Left pane, 9th from top: Dictation.
4. Click button: Dictation Commands...
5. Left Pane> User >.. Click on the + at the bottom and create an <undefined command>
6. Click on <undefined command>
7. Fill in: When I say: Type a name, e.g. Olga
8. Perform: Choose... > Run Workflow > Other... > type "siri" in the search on top right. Choose Siri.app
9. Right Pane: Check mark: Enable the dictation keyword phrase: Type anything you want, e.g. Paslushe
Now you can say "Paslushe Olga" and Siri will pop up.
Note1: The only thing it cannot do is that if you ask: "What is your name?" she will respond as: "Мена зовуть? Siri. впрочем, это не новость." meaning "My Name? It is Siri. However that is not news."
In English, if you ask: "What is your name?" she will answer "My name is Siri, but you knew that already."
Note 2: You can make more commands so that you can say other names as well.