Understanding "Delete Account"

Hi, I tried researching this, but came up with nothing. Can someone please explain what happens when a user deletes their account? On my test account, I deleted my account. Before I did that, I posted a test post to see what happens after my account is deleted. The post was still on the stream, which confused me. I then tried to log back in to see if the test account was deactivated, couldn't log in. Only when I deleted the test account, the post disappeared. After reading some topics here on the forum, this is what I came up:

User deletes account, posts, Groups & Pages, galleries, and audios created by the user remain on the site. The only way the user's information (Addressed earlier) can be removed is when the site admin deletes their account from the ACP?

Shouldn't the user's data be deleted when the user deletes their account? Need some clarification for my site's polices.

Thank you,
Steve