There's nothing that implies natural causes in the word "wildfire".
Definitions here "wildfire, defined as largescale forest loss resulting from the burning of
forest vegetation with no visible human conversion or agricultural activity afterward". There is clear agricultural activity immediately shown after the vast majority of Brazilian fires. https://science.sciencemag.org/content/sci/361/6407/1108.ful...
"Any large fire that spreads rapidly and is hard to extinguish."
I'm using the dictionary definition of the word.
So you would honestly describe the Great Chicago Fire of 1871 which clearly was large, spread rapidly, and was hard to extinguish as a "wildfire"?