Michele, ALL of Geni.com including search engines can read this. The discussions are for genealogical purposes, so perhaps a rant about "Melanie's biological father" should go in your "Family Discussions."
There is no way to "make it private." This is a Public Forum. Family is private to a point, where just your family sees it.
In order for it to disappear, you have to delete your posts and then Erica and myself will delete ours. After we all delete, the post will go away.