I hate when a site doesn't let me delete my account. Apparently, drupal.org hasn't been able to implement this feature in more than 11 years already:
While it was a long running thing that the Drupal product couldn't let users delete or disable their own accounts, the issue you linked was resolved[1] in 2009 (more than 4 years ago) and made it into Drupal 7.
Unfortunately, Drupal.org is still running on Drupal 6 and its upgrade to Drupal 7 has been met with repeated setbacks and delays[2] with no ETA[3]. Definitely unfortunate.
Edit: looks like they're accepting requests for account deletion via password@association.drupal.org for the time being.[4]
[1]: https://drupal.org/node/8#comment-1188824
[2]: https://association.drupal.org/node/17738
[3]: https://association.drupal.org/comment/4263#comment-4263
[4]: https://drupal.org/news/130529SecurityUpdate#comment-7475090
In a nutshell, that line sums up everything that's wrong with drupal.
An unwillingness to push through an upgrade to a site containing millions of user accounts and tens of millions of pages of content before it's ready is, to me, an example of what's right with Drupal.
I shouldn't be considered a fly trapped in amber just because I happened to want to try a site out, particularly when so many require an email address or facebook account to sign up or sign in (and in some cases, to find out what it is the service does.) Hashing passwords is extra work too. Common courtesy towards users should count towards the minimal amount of work necessary for a site. It's not as if the users who want to leave, now want to stay because you want to hold on to their data.