Earlier quoted context omitted.
This is a really bleak way to look at digital devices and their role in the world. Should you only write things you want the world to read on a computer, and for everything else, just use pen and paper?
Yes. Anything you write into your computer has the potential to be shared. The same way anything you write and send in the mail has the potential to be shared.
Some digital activity should be considered private, and violating that privacy should have legal and social consequences.