Not much of a response. The interview treated Koch influence on politics as a forgone conclusion. (Because it is and Charles didn't seem to argue otherwise).
The point of the interview was to learn about his personal philosophy. Something of which wouldn't be of much interest were it not for his huge amount of influence (that, again, no one is arguing).
As for the final thrust of this response, on how Koch helped stopped a supreme Court nominee, it's likely nothing nefarious. It would be the same as any citizen. Contact your congress people. Difference is, they are going to really listen to the billionaire donating money to their campaign a bit more than your average Joe.
It's legal because of the Citizens United Supreme Court decision, but I hope that, before the Koch brothers pass away, we'll see a constitutional amendment overturning this egregious decision.
The idea that money = speech is toxic to democracy.
I don't see how to tackle the fundamental difficulty of regulating "soft money". We can surely do better than McCain-Feingold, which leaves the "call Senator X and tell him it makes you sad when he kicks puppies" loophole. However, it's going to be difficult at best to have meaningful legislation against "awareness" ads or even more abstract culture war stuff like what the NRA has produced lately. I think we have less of a legislative problem than a culture problem.
So, what makes newspaper exempt from this? They can publish opinion pieces on who to support, and they are spending a lot of money in producing newspaper. Surely that _should_ violate McCain-Feingold? Except it didn't, because there was a special exemption for media. What makes that fair?
Let's say I'm an individual, and I support Santa Claus for president. But I'm also a famous personality, and I spend a million dollars to put on a free speaking tour where I support Santa Claus for president. Aren't I using money to support my speech? I'm not just using my mouth, I'm using my money to pursue my first amendment rights.
It's never been illegal in the US to support an issue to the fullest extent of your financial capabilities. You can make statements into a public forum with your every last dollar.
It had been, for decades, illegal for one person to support one specific candidate/campaign. It was never quite enforced such that it made a huge difference (shell companies, PACs, etc make it easy to skirt rules and funnel campaign support) and candidates get progressively better at asking for "support" without actually making the tit-for-tat which moves it from the "lobbying" arena to "bribery".
Also, IIRC that ruling established the precedent needed for SuperPACs and moved the individual contribution threshold.
