> the issue is granting extra free speech rights
Nope. It is about prohibiting corporations and unions from using their funds to make independent expenditures for speech [1].
> In fact, some companies having a tendency to curb free speech through contracts denying people the right to talk about certain things.
Your example is strange. Such contracts are not imposed by the government.
> corporations get used to dodge personal liability by their owners and employees
You should clarify what you mean by this and how it is relevant to the issue at hand.