So the traditional answer for these two groups (at least the ones in America) has always been "businesses have the right to fore any employee for any reason".
Now I get the sense that with the massive corporate abuse of power on free speech as well as this subject, opinions may be shifting.
But I am very interested in knowing what people think about this and why.
I'm a libertarian (or voluntarist really) and agree with TheImp, I believe in free association for individuals (and small companies they start) but at some point a business stops being an extension of the owner(s) desires and becomes its own beast, a service to the public and potentially an arm of the state. At that point it shouldn't get any "rights" whatsoever.
I'm not sure becoming a publicly traded corporation is the line either.