The author already claims he has access to professional spamming tools. All he has to do is spam people on craigslist pretending to be AirBnB in a way that can't be traceable to AirBnB. Then he writes an article complaining about AirBnB and asks "why would they hide behind shady tactics?"

You get maximum impact if you wait two years and post when your competitor gets really big so everything is forgotten and really untraceable.