Social media policies

Seems free speech is alive and well in the US ...
"Most of the social media policies that we've been presented are very, very overbroad," Solomon said in an interview. "They say you can't disparage or criticize the company in any way on social media, and that is not true under the law."  ... Doreen Davis, a management-side labor lawyer based in Philadelphia, said many of her corporate clients are often "surprised and upset" when they learn they can't simply terminate employees for talking about work online.
Employers should develop sound, legally-sanctioned policies concerning what employees can and can't say about them on Facebook or whatever, but more importantly they need to provide mechanisms for employees to voice genuine grievances and have them addressed properly by management, without fear of persecution or recrimination.  That's the real issue here, isn't it? And it's a governance matter in my book.

So why is it that whistleblowers' hotlines are still as rare as rocking horse poo?