Obvious spamming is one thing, and posting a dissenting view is quite another. The main point is, what you have called for is the removal of individuals simply because you don't like what they say.
And even if someone was posting a great amount of spam, I'd rather see the person privately reprimanded, and even still allowed to keep their account provided it doesn't continue. I'd prefer it if we didn't resort to banning and publicly branding individuals as traitors to the cause, as you have done in this case, for what I consider to be a far lesser offense than repeated spamming.
I understand that these forums are private property, but I consider that to be irrelevant given the context. Certainly, the owners of these forums have the right to do as they please, but if they were to do as you have suggested, then I believe that would be antithetical to the messages of freedom and liberty that we claim to adhere to. How can we purport to be the defenders of (among other things) free-speech rights under the law, when we will not even allow others that freedom on a voluntary basis?
I want you to know that I mean no offense by this, but I hope you can see that the position you defend has an authoritarian bent. Being a Ron Paul supporter, I would assume that obviously, authoritarianism is not something that you would truly desire to endorse, so I implore you to reconsider your position. The choice, ultimately, is up to you, but I think you would be served well to remember these words:
"I detest what you have to say, yet I will defend to the death your right to say it." ~Voltaire