Maybe debunked was not exactly the right word (I'm always struggeling with the English language) but the argument seems very weak.
" In 2004, firearms were used to murder 11,344 people in the United States, compared with 184 in Canada and 73 in England. Why are murders from firearms so much lower in Canada and England?"
You weren't talking about semi-automatic weapons here. So this sentence refers to concealed semi automatic weapons? I can shoot you just as well will a colt that I carry openly.
"The first thing Fascists usually try to do is silencing the opposition."