According to all the above comment Freedom of Speech is a Myth.
Corporations cannot be criticized by employees publicly.
We have gone backwards by a hundred years
No, Ace, your rights to criticize still exist, there's nothing to stop you saying it (up to the point of libel).
HOWEVER right cut both ways. Companys have rights as to what they expect from their employees. You are paid in order that your service benefit the company.
If you actions make that not so, the company has the right to terminate you.
Is it the case that you want your rights protected, but companies rights curtailed?