Several random thoughts on this wonderful case:
Nothing about this case says anything about corporations as individuals. The first amendment reads: Congress shall make no law ... abridging the freedom of speech.
If me, my brother Darryl and my other brother Darryl decide to take out an ad on TV saying that politician Bob is a douche and you shouldn't vote for him that's OK. If we own a private business - that's OK. If we have incorporated - that's not OK? I don't get the distinction. I certainly don't agree with giving Congress the ability to decide who can and who cannot speak or what they can say during certain portions of the year.
This specific case was the showing of an anti-Hillary movie within 100 days of an election. I assume that people that are upset about this ruling would be OK if it were illegal to show Fahrenheit 9/11 within 100 days of an election? That seems more than a little odd to me. Where does the line get drawn? Does Wag the Dog count as campaign speech? Or Inconvenient Truth? Why does GE get to say anything it wants, but Microsoft can't? Do blogs count as media now? Or is it only 'traditional' media that should be exempted from barriers to political speech during a campaign?
Once you decide that it is OK to draw lines on who can and cannot speak you have to give someone the power to decide who and what those things are. And guess what? Those rules are more likely to benefit the well connected than the average Joe.
Big corporations don't need help influencing the process - they already are. The barriers are only really effective against those that don't already have power.