@Roddy3 All you have to do is just decline the change of dates and the reservation ends when the original terms are over. If the guest is actually displaying a derogatory attitude I would probably call Airbnb and get it on the record.
You don't have to accept anyone's extension. Just say "No thank you"
Do not go into details.
Your dehumanization of this guest is seething . Best to keep it to yourself.
Perhaps he is racist, xenophobic and misogynistic. But be absolutely sure if you to publish.