Corporations exist to limit the liability of owners, in particular to decrease risk to owners. Given that owners of corporations are given such special treatment, it makes perfect sense that such an organization does not inherit the rights of the citizens that are protected from the results of the corporation's actions.
Yes. And recall that, in the US before that late 1890s, only public-interest corporations were legal. Because that was the tradeoff for the ability to arbitrarily concentrate capital, with limited-liability. If a corporation violated its public-interest charter, it could be dissolved.
But then the railroad corporations got big and rich enough to buy off Congress and the Supreme Court. They got human rights before women did ;)
Corporate personhood cuts both ways. If a corporation doesn't have free speech rights or any of the rights of a person, does it have legal obligations? Can it be sued? Can it enter into a contract and be held to it's terms? The ability of courts to hold corporations accountable under the law and the constitution, in the United States, also relies on the notion of corporate personhood.
The notion that people do not lose their legal and constitutional rights when acting collectively seems to me to be a very dangerous one to want to revoke, and it's not obvious to me that any legal right granted by a specific law should entail any unstated or implicit revocation of any other such rights.
Newspapers are corporations. Do they have no right of free speech? OK so you could start carving out all sorts of technical exceptions, but that way lies madness and a bonanza for the legal profession at little benefit so far as I can see.
Finally as to limited liability, as I understand it limited liability corporations are generally subject to additional taxes as a cost of their liability privileges and that seems to me to be a practical and proportionate arrangement.
All corporations have limited liability, the limits vary as do the requirements. The fact is, they only exist because the government permits them and assigns these rules, there's no practical reason that non-living entities cannot be restricted in exchange for those benefits assigned. Except now it would take a constitutional amendment to overcome supreme court precedent.
What that means in practice is that corporations that are friendly to the establishment can say whatever they want, and those that oppose the establishment are subject to prosecution.
Evidence? This was a relatively recent decision. If what you say is true, there should be mountains of relatively recent evidence for it in the US. Otherwise you're just promoting a groundless personal theory.
This is human nature. Chelsea Manning got prosecuted, while all the other leakers don't. People with bumper stickers are more likely to get pulled over. Look at what European countries do to crack down on speech.