I never saw that, FR has many Rudy and Giuliani supporters, you just said that you are among them.
I think the people that Jim bans are people that become trolls, that become so loud and persistent and nasty in pushing a non conservative agenda or candidate, that they start hijacking threads and stopping conservative discussion and become a serious hindrance to the free flow of useful information and exchange here.
Another liberal type troll that I think gets banned is someone that does the above on a new account, when it becomes clear that they are purely here to disrupt and have no other conservative value or interest to freerepublic, then Jim may dump them pretty quick, I'm sure you have seen that nooby troll sign up, that was just here for grins and giggles.
If you mean that all candidates should be given equal footing on freerepublic, then think about it a little more. FReepublic is a conservative web site, intended to advance conservatism and conservative candidates, once a candidate is seen as clearly an enemy to those purposes then he becomes our enemy and must be stopped, that is what political activism is about.
I don't know what your limits are so it is hard for me to think of an example that would lead you to accept the necessity of banning some of a anti-conservative candidates more radical, obstinate, and dominating advocates, but Jim has his own vision of the purpose of freerepublic and it's influence, and his limit was Rudy Giuliani, and is now Mitt Romney.
Liberal candidates such as pro abortion candidate Rudy Giuliani cannot be advanced here without his defenders trying to win at the very least, tolerance for abortion and their other failings, did you think that Jim Robinson would let his forum come to be used in advancing the abortion movement into the very core of conservative activism here at FR, or that he would block that cancer to free-up and return to the discussion of acceptable, conservative candidates that we can advance to victory over the cancerous one?