Oh dear Viviana,
You have my sympathies. I was the OP on this thread, and although it was some time ago now I remember how unpleasant make me feel. It defeats the object of offering your space to AirBNB guests. It's meant to be the 'sharing community' and hopefully one is able to share it with like-minded souls, or at least friendly people, just to enrich your life a little bit.
But it seems these people are treating AirBNB like a harsh, commercial transaction. Why dont they just go to a hotel?
I do agree with you that AirBNB need to try to find a way screening out rude and belligerent characters, who are aiming to be guests. If they are reported they should be struck off the system immediately.
When the host is offering up their home, they're offering an awful lot more in the way of trust, faith and belief in other people: in short – the model of the "sharing community". Rude guests are not part of the "sharing committee". Instead they are part of the "where's my money?" old community.
(incidentally, you should be able to withdraw your pre-approval on your dashboard).
Best of luck – and "keep the faith". I havent had any other 'bad apples' since then, thank goodness.
Carey