Alain,
WHAAAT? It is unbelievable how you have been treated, by both the guest and airbnb.
All these cases beg the question: What is the tipping point for hosts? At what point is there either a different service that will be preferred by hosts, or at what point will short term renting at all not be preferrable?
If the problems are prevalent and terrible enough, should hosts stop using the site as a matter of principle? People are now set up after years of depending on their income from this service, and they can snake in bad-to-horrible-to-unethical policy changes that all are forced to accept or beasically change the entire source of their income.
Alain, I think if I were you I would ignore all of these requests from the guests, ignore all of the comunications from airbnb about this guest, block him if you can, and move on. Ignore. Ignore. Ignore. That's what they have really done to you and you are well within your rights to do the same. If there is a bad review left, leave a very courteous reply to all your future potential guests and make him look like an **bleep** that he is.