Why are employers allowed to demand facebook passwords?

[Galen]

You are free to challenge them on the constitutionality of it.

I would hazard a guess that such practices would not be valued or allowed.

The constitution is a very vague piece of writing and an unliving piece of matter. It does not dance to life and do your work for you: "yup, Mark is right! I'm totally against that!"

People have to do the work, challenge the practice, file a suit, and explain to a judge why it is far better for society, all factors considered, to do X instead of Y. We go under the fiction of saying the eventual conclusions and decisions were based on a piece of paper that mentions life, liberty, and happiness, because that piece of paper is seen as foundational and symbolic of what we value in our country, and so it lends some authority to our decisions.

But don't get too sucked into the fiction and think that the constitution speaks very much at all. More importantly, do not go under the delusion that it speaks (what little it does) for itself. Passionate citizens fight to articulate and explain why their views should be adopted, some laws or practices be made, and other stricken down.