Clearly, what you're saying is at least partially false. Reporters and editors who work at the NY Times corporation express their own opinions all the time. The people who worked for Citizens United obviously were expressing their own opinions in the movie they made.
Still, that's not the point at all. People who work for a corporation are employed to do their job. Sometimes that job involves expressing their opinions and sometimes that job requires NOT expressing their opinions.
I've been pretty clear and consistent that what I'm talking about are the people who organize and own the corporation. For example, we don't talk about the guy who is hired to paste up a billboard as being the one exercising his first amendment rights, we talk about the people who paid for the billboard to be printed and put up. It's not the guy who runs the printing press whose rights are infringed when the owner of a paper is told he isn't allowed to print what he wants about a candidate. It's not the broadcast engineer whose rights are infringed when a company created for the express purpose of producing a political movie is told they'll be fined if they broadcast it within 30 days of an election. It's not their purposes which are being frustrated, it's obviously the purpose of the owners being frustrated.
A corporation is a tool for the owners to accomplish a particular purpose. Free speech may be incidental to that purpose, but it also may be directly related to that purpose. I'm sorry that you limit people's speech and publishing such that you prefer to ban their use of a corporation to exercise it, but to me that's just thugs in government trying to use their power to shut people up they either disagree with or they don't control, or both.
"Campaign finance" laws are generally about one thing, doing what Congress thinks will help keep them in office and give them more control and an advantage in elections. That's not necessarily why regular people push them, but that's why Congress and President's pass them.
Some people react to free speech they don't approve of by looking for some excuse for the government to stop it using some technicality they think might pass muster in the USSC. Well, in this particular case the USSC finally did the right thing and protected people's rights to publish their political ideas using a corporation.
Just because people create a separate legal entity for the purpose of exercising their rights doesn't mean "Hey, we gotcha, we found a way to protect politicians from your speech!" is going to fly. It's a B.S. argument designed to use an excuse to limit people's speech. Well, guess what, the first amendment says "Congress shall make no law respecting ..." and there's no exception in there for corporations or for people working through a corporation, or for FCC broadcast licensees. It just says "... abridging the freedom of speech, or of the press". Saying you can't broadcast a political movie within 30 days of an election because it's political and might influence the election... that's EXACTLY what the first amendment is supposed to protect against. As it turns out, five Justices of the USSC agree with that.