Yes, I am in favour of the obscene publications Act.
Odd, therefore, that the original object of your ire (one short story in a minor work by Anais Nin) hasn't awakened the interest of the Crown Prosecution Service in the near-forty years since it was published. If your threshold for outrage is the OPA, then calm yourself, because there is no way on earth that a prosecution under the OPA would, or could, be brought against any of the books that are exciting outrage on this thread. There's more chance of Fifty Shades of Grey being prosecuted. You can read the charging guidelines here.
I think 99.9999999 % of publications end up being effectively self censored by publishers, distributes or by the market itself.
Or circulates on the Internet, well away from prying eyes. Worrying about what's sold by overground publishers on public websites does seem all rather 20th century.
Do you seriously think that someone with an interest in child erotica would be purchasing near-unreadable Penguin Classics by minor mid-20th century writers? Have you actually read Delta of Venus, or are you just being outraged at a second remove, in the manner of bearded men with effigies of Salman Rushdie? "Instead of answering her as soon as he saw her hair grow electric, her face more vivid, her eyes like lightning, her body restless and jerky like a racehorse’s, he retired behind this wall of objective understanding, this gentle testing and acceptance of her, just as one watches an animal in the zoo and smiles at his antics, but is not drawn into this mood. It was this which left Lilith in a state of isolation - indeed, like a wild animal in an absolute desert." At least Nabokov could write.