As the article indicates, most of the fires are from cooking rather than arson. But a person lacking expertise whose consciousness may be altered by recreational chemicals and/or mental illness building a cooking fire in a dry park setting is an out-of-control fire waiting to happen. Sometimes people die or are injured, often property is damaged, loads of fire department time is consumed.
Any county stuporvisor or city clownsel member who couldn't have foreseen this can't safely tie their shoes in the morning.