Great first post welcome to the site.And what is a 5 star rating for a motorcycle anyway? How far you get thrown???
While it's not a car, it is being designed to achieve 5 stars on the same tests that cars go through. While it is true that actual testing has not commenced, computer simulations are very good these days and most vehicles perform as simulated in the actual tests.
Your naysayer friends can search for their concerns here and find the answers from posts over the past 4 months or so.