As a guest, it's sketchy because the property is usually not-well-cared-for and they've often pissed off the neighbors because they can't deal with nuisance guests.
This is a gross generalization. I've stayed at many properties where the person was truly into hospitality and created a much better experience than I would get staying in someone's spare bedroom that they've never rented out before. People who host regularly often tend to leave things stocked in the house that come in handy, have maps of their favorite local restaurants and attractions, etc. whereas a small time host simply hasn't had time (or often inclination) to do those things.
Professional hosts also often have much better systems for key handoff, people you can call if something goes wrong, etc.
This isn't responsive to his point. Nobody is saying you're a nuisance guest, or that you haven't met hosts who are concerned about nuisance guests. They're saying that nuisance guests are a thing that happens, which seems self-evidently true.
Actually I responded directly to the claim that the professional properties are "usually not-well-cared-for" which was an unsubstantiated claim that is clearly way too broad of a generalization.
As far as nuisance guests, I've said elsewhere in the thread that I think the cities should not hesitate to give out large fines for recurring noise violations from one address. Party houses and frats also make a lot of noise even though they have nothing to do with vacation rentals. Banning Airbnb is a less direct solution to that problem than simply passing and enforcing noise regulations. People will just rent on Craigslist and make as much noise as they want if you don't.
Craigslist existed (and was probably more important!) long before Airbnb, and the nuisance tenant phenomenon seems to track Airbnb's popularity, not Craigslist. So that's not a very persuasive argument.
I’m seeing you say is that you, the “host”, and Airbnb are quite happy with the way you’ve been able to split the benefits of pushing externalities onto others.
Such honor among thieves is perhaps surprising but in the end rather beside the point.
Professional hosts also often have much better systems for key handoff, people you can call if something goes wrong, etc.