If they were dealing with the FDA rather than the NHTSA, they would have received a Notification, and if the false labeling was not removed, Tesla would be facing fines and even a consent decree, including federal agents being sent to their production facility to lock down the building until they establish compliance. Just because the blog post is still up doesn’t mean it’s correct.
The NHTSA test does it’s best to simulate certain crash conditions, but it can’t be extrapolated to overall safety in every situation. Tesla’s statement is a blanket statement that doesn’t actually reflect the science behind the testing, and thus misrepresents its products to consumers.