Here (copy) is a diagram.

Tesla's algorithm is supposed to be autonomous for freeways, not for highways with intersections, like this. The algorithm doing what it was supposed to do would not have prevented a crash. But the algorithm was supposed to eventually apply the brakes. Its failure to do so was a real failure of the algorithm. The driver also erred in failing to brake, probably because he was inappropriately relying on the algorithm. Maybe this was a difficult situation and he could not be expected to prevent a crash, but his failure to brake at all is a bad sign.

It was obvious when Telsa first released this that people were using it inappropriately. I think that they have released updates to encourage better use, but I don't know how successful they were.