I've just been reading a thread which is now deleted as it was a reverse; this does bother me as often on reverse threads people have spent quite a lot of time formulating replies which are then lost.
I think about users and lurkers who may gain some insight into their own situations by reading one of those replies, and that leads me to question the deletion policy.
The only people who benefit from a reverse being deleted is the OP, who is probably using a different name so needs no protection. Now, admittedly I had quite a lot of sympathy for the OP of that particular thread, and I don't get the antipathy towards reverses anyway, but why not just close the thread rather than render everyone's time and effort useless by deleting the whole thing (and possibly doing a disservice to some poor soul out there)?