As an automobile manufacturer, there is no good conscience reasoning that Tesla is unaware that active restraint and airbag systems of today are far more nuanced and weigh multiple criteria when deciding to deploy (as compared to initial/early implementations, which were essentially "if collision=true and speed >= X mph then deploy"). You can have a very significant incident (two that I've witnessed recently as a paramedic involved vehicles into stationary objects at ~30mph) without airbag deployment. But if that was a Tesla in FSD that hit something at 30mph and didn't deploy airbags, well, that's not an accident according to Tesla.
That also doesn't account for "incident was so catastrophic that restraint systems could not deploy", also "not counted" by Tesla. Or just as egregious, "systems failed to deploy for any reason up to and including poor assembly line quality control", also not an accident and also "not counted".