But Tesla is using that metric in a place most normally don't, and they are doing that purposely as elsewhere they use an in house estimation like everyone else.
No gasoline car uses the EPA fuel economy to do it's range estimation, EVEN WHEN IT WOULD BE BETTER FOR THEM TO DO SO, because it's wrong enough often enough to make a range estimation using it lose significant value.
Tesla has made a choice to stray from normal industry practice. If they have done so in an attempt to sway customers with the incorrect numbers, that should be considered fraud. That's pretty damn difficult to prove as a crime, but not hard to make likely in a civil case.