They could easily say that they have a suspect in custody and that the evidence is sealed. At this point, they're poisoning any possible jury and setting themselves up for a mistrial. Also, the evidence isn't slam dunk:
1) "driver had appeared agitated and angry" according to passengers
2) circumstantial evidence that he was near the fire when it started -> he saw the fire and called 911 multiple times to report it.
3) He asked ChatGPT a question: "Are you at fault if a fire is lift [sic] because of your cigarettes?"
4) They mention he prompted ChatGPT months earlier to generate an image of a fire, but they don't tell us the prompt.
5) He listened to a rap song, of which he probably was not watching the music video with the fires
He may have done it, but this isn't pride in the evidence they have, it's desperation to find someone to blame and likely exonerate the state for not putting out the fire as well. The power distribution system in California is notorious for starting fires. So there's public, political and private financial incentive to find a fall guy. Wildfires are ravaging California, so it's normal to do web searches and talk to LLMs about fires and fire safety. If this guy were as obsessed with fire as they claim, there would be *a lot* more material to report about his obsession.