Kokesh indeed screwed up. He should know the limits of where he can go and he is IMHO a bit way over his head and lacks sophistication. A bit more humbleness can't hurt. In contrast Judge Napolitano knows very well what and how to say, that he cannot publicly endorse a candidate but can come very close to it and the viewer can fill in the blanks for themselves and one actually limits your appeal if you come off hyper partisan.
Dr. Paul cannot waste his time too much by preaching to the choir. I think one can safely assume that most if not all viewers of Kokesh's program are Ron Paul (or Gary Johnson) supporters. Benton has the responsibility of getting Dr. Paul on shows with viewers that are undecided or support another candidate, but can be swayed over to Dr. Paul with an open mind. In this context it is much more important that Dr. Paul appear on a local TV or radio station than on Kokesh. Some of RT's other presenters are in any case very favorable towards Dr. Paul.
Yes, I think RT ended the deal with Kokesh because whether or not the FEC complaint is successful or justified or not, they want to spare themselves an embarrassment, especially as they are expanding and specialize in covering points of view that are being neglected by the US MSM. They have Tom Hartmann's program and Tom is actually more like a Green party and sen. Bernie Sanders supporter actually (he used to be a libertarian years ago, thus know some of the arguments). And RT thought they also needed a libertarian program, e.g. not a neocon. and as they are also anti-war of aggression, they are fine with peace broadcasters from the "left" and "right".
To fill Kokesh's vacuum, I hope they get someone like peter Schiff, e.g. give him a program. And Schiff could IMHO do a much better, smarter and professional job than Kokesh. Kokesh has some talents, but he should first gain some more life-experience and it will take some time still to get over his PTSD. Someone like Schiff will also get guests with which he and us do not agree with, and also attract more viewers, who could be persuaded and think how he can educate about economics!