Earlier quoted context omitted.
Is your question why privacy is important, or are you thinking of something else?
They have to respect our privacy. The moment they don't, it will cause widespread outrage. Once I realized that, it was hard to think of reasons why their actions are wrong.
https://www.forbes.com/sites/kashmirhill/2014/06/28/facebook...
That's only one instance of why you should care. There are plenty of others.