If social media platforms do not legally provide an expectation of privacy, as Facebook has recently claimed in US court[1], why should users expect otherwise?

If social media platforms do not legally provide an expectation of privacy, as Facebook has recently claimed in US court[1], why should users expect otherwise? [1]https://www.nytimes.com/2019/06/18/opinion/facebook-court-privacy.html https://www.nytimes.com/2019/06/18/opinion/facebook-court-pr...