That seems to be irrelevant. He started a fire in a public place. That can be a dangerous thing to do.
Same issue. I have no problem with it as long as it is done safely.
The issue isn’t what is burned. It’s how it’s done. Reading nothing other than the single sentence included in the link, the guy was convicted of a public order offense. I suspect in the US we would call it disorderly conduct. Starting fires in public places could easily be disorderly. Start a fire in a designed space for burning? Fine. Nothing disorderly about that. Start a fire on a busy street corner? Not fine.
–Peter