Unfortunatly, many of us have problems dealing with difficult people.
The person in question has some very strong beliefs and will take whatever measures are necessary to defend them. The fact that those beliefs are rooted in truth makes it difficult to shake them. The problem comes from him seeing those beliefs as the most important thing in the world, and others seing those beliefs as one factor out of many.
You can argue all you want with him, you can use all the math, science, and logic you want, but in the end you will not change those beliefs. This is an argument that can not be won as both sides know that they are right and therefore can not compromise... in the meantime bad feelings and acrimony build up.
In the future, if you run into someone like that (and there will be more) just let it drop... don't waste your time, those who agree will agree, those who disagree will disagree, and tens of thousands of posts will just dig the trenches deeper.
And to the moderators:
Sometimes, for the good of the tree, you have to prune off a limb. You can't let things descend into chaos. Many years ago, in the time of text message boards, there was a group called rec.boats.paddle. There was one particular member, who claimed to be the inventor of a safety device, (it was in common use before he was born), who was convinced that there was a government conspiracy to prevent sales of his device and how this conspiracy was killing thousands of childern through unnecessary drownings... every thread on every topic was hijacked by the diatribe and it ended up destroying the group. CanonRumors can follow the same trajectory without moderation.... Thank you for finally stepping in.