I'd say those batteries were justified in their explosion given the damage to the car. For the tree to go far enough into the front of the car to split the main pack apart and scatter modules all over the road, they were going entirely too fast for any public road.
Ignoring it's a Tesla, it's a wreck where a car hit a tree at a high rate of speed, caught on fire, and the people in the car got killed. Hate to say it, but this happens every day. The exploding batteries were a result of physical damage, the same as almost every other EV battery fire that has occurred.