Your conclusion relies on the - quite faulty - assumption that "situations that inherently difficult for FSD to handle" are automatically "also more dangerous for human drivers". In snowy conditions, humans do just fine, generally, at following "lanes", be they the actual lane, or the safest route that everyone else is following. Humans are also capable of deducting lane direction, orientation, even when there are contradictory/old lane markings on the road, a situation FSD regularly causes danger in.

Or that that negative effect is lost in the orders of magnitude of "all human drivers across all miles" versus FSD.