I know it's too late to change anything, but when I write articles, I avoid calling someone out by name or even using the word "You," especially in the middle of the article, as it could be construed as a personal attack. In a debate, the idea is to make your self sound more intelligent than the other individual, not to belittle or place blame to them. I probably would have started the rebuttal by referencing the article by his name. Your first two short paragraphs were perfect for this, but in the middle, I would use facts (Which you did a great job of doing with references to laws), not the individual's name.
For example:
"Just because you were traumatized, sir, does not mean anyone else was."
"And just to educate Mr. Granvold, I was open carrying, not concealed carrying. If I was carrying concealed, how would you know?"
Thank you for pointing out the difference between concealed carry and open carry; however, sentences aren't supposed to start with transition words. MKEgal came up with some excellent examples too.
"Did anyone running away, scream, or fainting? I didn't notice an exodus."
"Openly carrying a firearm is not the same as concealed carry, and if I was carrying concealed, which I am also legally able to do, no one would have known I was."
Hope this helps.