I'm saying that the VAST MAJORITY of people who will speak of the NHL team will not be residents of the area, and their USAGE will likely be: "Vegas".
Now, the minority can whine and complain about the official name of the city, but it won't change the fact that language evolves based on usage and most people will not speak of "Las Vegas" when referring to the team.
So, whether the team name will be listed officially as that of the city or most common usage, the latter will prevail in most communication. So, urinate against the wind if you like. It'll be silly, as it won't make much difference.