Cynically, to make a documentary and get articles written. None of the rules they mention seem that extreme, they're just wording it in an unusual way.
Same nefarious reasons corporations were given "personhood". Is it illegal to "assult" trees now? If someone pisses on a tree, are they going to call in the SVU? The legal system isn't a toy. Trees, in the general sense, don't need extra laws, the ones that need protecting are already covered by property law.