Due to the fact that you do not need to provide any personal information, and Wikipedia needs to track who made what changes, the site is not on the black list.
Nevertheless, if you still fear your privacy: you cannot delete your account - only change your login. See http://en.wikipedia.org/wiki/Wikipedia:FAQ#How_do_I_change_my_username.2Fdelete_my_account.3F
Publicly visible text/images often aren't properly deleted even when you succeed in deleting an account. Try editing or deleting them manually before deleting the account itself. If you're unsure what happens to your tracks you can always contact Wikipedia and ask personally. By the way, deletion requests don't necessarily mean your data will actually be deleted (e.g. due to legal obligations).
If you signed up for Wikipedia using a third-party login such as Facebook or Twitter, you probably want to revoke all access from Wikipedia. Click the icon below to find out how.