Well you can contact them, but you get the same response. Deleting an account because of all the other threads, responses and member numbers is not done here. Even with a limited amount of posts, it still will not be done.
If you are serious about deleting your online presence here, go to all the threads you posted in, delete the content and type the word, "gone" or something like that.
Then empty out all your information or place false things like comic book names or band names.
Then change your password by typing a bunch of nonsense you will not remember. Log off. And you have basically deleted yourself from the site.
Rob