And your purpose of the ad hominem attack demonstrates what exactly? Was that a determined attack? Or was the insult prepared under the assumption that RC can change his mind?
RC's mind can be changed and that doesn't contradict determinism in the slightest. It is a simple fact that after RC reads this his mind will be changed such that it has a memory of reading this, (at least for a short while and RC has no choice in the matter. It will simply be a chain of physical causality that occurs.
RC's brain is not some isolated system which you and I are unable to influence. His brain exists in a complex web of causality which includes among other things, your brain and mine.
Now my impression is that RC has strong emotional reasons to avoid facing the fact that he is wrong about some things. So in some regards he might be considered learning disabled and harder to effectively influence than is normal, but it would be silly to think that determinism conflicts with it being possible to influence the working of RC's mind.
Whether or not you believe in freewill or not, attacking and insulting functions under the assumption of freewill; otherwise what's the point? Arguing determinism as if a person has the freewill to change his mind is hilarious to me...
People's minds changing isn't a matter of freewill, it is a matter of physics. Consider a person who is insulted or ridiculed and blushes in embarrassment, or tears up. Do you honestly think that that person's mind hasn't been affected in a way utterly independent of free will?
Furthermore, with some psychological understanding, other people's will can be influenced subconsciously to result in them behaving in ways that they have no conscious intention of behaving in. For example, think about reverse psychology.