When you post something on the internet, unless you give out user IDS and passwords or block any random yahoo who wants to from seeing your stuff, THEY CAN ALL SEE IT!!!
It's no one's problem but yours, when you get down to it. Either post to Friends Only and be proactive, don't post at all and TOTALLY circumvent the issue, or accept that if you make it a public post - it's a public post.
Honestly, I don't see where the crime is or why any of this matters in the least, but hey - bitch on if you must!