A wild fire has a slim chance of happening and so does a death of a bystander when you crash a plane into unpopulated forest. The danger is so minimal here that what he did is clearly will not lead to accidental injury or deaths of others. It's Just stupid, like a person who road rages and rams into a parked car, unoccupied car.
The consequences here should be a fine and loss of pilots license. Jail time isn't even a discussion here.