Most water based acrylic paints still have a polymer emulsion base, which is plastic. Those of us who use them are forever worrying about the best and least harmful way to dispose of leftover paint. They leave a footprint in the natural environment that is not benign. There ARE other earth-friendly paints with a corn starch base. But I would guess that is not what Nocket used since she did not say that. And I would argue that urban graffiti art--which I love and value--is different than contaminating protected national parks and wild ecosystems.
"My predominant feeling is one of gratitude. I have loved and been loved;I have been given much and I have given something in return...Above all, I have been a sentient being, a thinking animal, on this beautiful planet, and that in itself has been an enormous privilege and an adventure." O. Sacks