Short of posts which contain other members' personal information, obscenely NSFW content, outright illegal stuff or which are posted by spambots, we generally don't delete any posts. That's what Complete Nonsense and Angry Ranting are for, and why so many posts get moved into there.
While there is obviously no way for you to personally verify this, you will find it difficult to sell your blockchain on such grounds to a forum where almost nobody has experienced their posts being deleted.