That shallow analysis assumes that public financing of elections is out of the question. In effect, it confers a sort of super citizenship upon corporations and wealthy people who fund political campaigns, and then ask for political favors. You, as a private citizen, get a dubious smidgeon of free speech when you give 50 bucks to a campaign. When it comes to giant corporations, on the other hand, the more money they have the more free speech they can buy. If they also own the media companies that own the news media, they become truly super duper citizens indeed.
If the learned members of the Supreme Court were actually concerned about free speech, as opposed to corporate-purchased airtime, their opinions would have contained a grain of concern for the corrupting influence of money in politics. Instead, the Supreme Court implies that if you want to have a voice in politics, you need to put your money where your mouth is. No money, no speech. In a sense, our system imposes a "voluntary poll tax" on those who give small political contributions. That money goes straight to media companies in the form of political ad revenues.
The end result of this money-driven political system is that corporations give huge contributions to candidates and expect something from the politicians in return. Average citizens, on the other hand, give small donations to politicians - adding up to millions of dollars - and all of those dollars are funneled to the very media corporations that are supposed to keep the public informed. The news media have an extremely vested interest in maintaining the status quo where every two years hundreds of millions of dollars are poured into their bank accounts for each election cycle. If public financing of elections ever became law in the United States, TV and radio stations would be forced to give free air time to all candidates. That is something that media corporations will never stand for. So expect to hear little about public financing from the news media, unless they have something very derogatory to say about it.
Write your senators today and demand public financing of elections, and while you're at it, demand a uniform US voting system that leaves an auditable paper trail.