I don’t think there are any faults in this that could not have been avoided with judgement, especially in the posting of sensitive information.
Unless you posted your street address, social security number, blood type, etc., you really have nothing to worry about. Your website probably gives more information than you’ve posted here. If you posted your login information for WP, you can change your admin password by going to Profiles after logging in. If you posted your login information for your web host, contact them and I’m sure they’ll be more than happy to help you change it.
Common sense (not that it really is) tells us that one shouldn’t post sensitive information ANYWHERE on the intarweb unless it is passworded/encrypted, and even then be wary, and certainly not in public forums.
I don’t see how wanting to remove personal information from a public board is wining.
Ignoring the whining part (more of demanding but that isn’t the issue), you should re-read that line you stated in response to Mr. Anonymous and take it to heart. One should never post personal information to a public board.