Right, except Joanna Public does have this expectation and continues to do so because of manifestly poor public education about the risks of the internet. We should literally have lessons about this stuff in schools.
And as another commenter stated, these things were not "online", they were "on a computer". If I can have no expectation of privacy for things I put on a computer then that is going to lead to no expectation of privacy under any circumstances. This stuff is going to have profound social consequences and something has to change.