@Sanjay89 "If you have nothing nice to say, don't say anything at all" is relevant to not telling your wife she's getting fat. It isn't relevant to getting advice for host/guest situations.
Not everyone sugar-coats their advice, so try not to take personal offense.
When someone comes here asking for advice, and then chooses to ignore advice they were given, then comes back asking for help because they ignored it, yes, you might get some tough love replies.
I concur with others who said it would have been better to refund the guy to start with, as he cancelled only an hour after booking.
There are many reasons why last-minute bookings can be problematic. I suggest you set advance notice to 2 days, so you don't get last minute bookings.
As far as the review goes, leave a review. Just say the guest cancelled an hour after booking and never stayed. You can also mention that he sent you nasty messages because you stuck to your cancellation policy.
And it's pointless to fret about a review you haven't even read yet. When it gets posted, you can leave a brief response to it if warranted.
You are wasting your time trying to get ahold of Airbnb if you think they will disallow a review. They won't, unless it violates review policy.