How exactly does what you pointed out -- "lack of familiarity with the subject" of geography -- constitute a "calling out" of their strong opinions on McAfee's character?

Total fucking non sequitur!

(Even trying it on paints you in an ever worse light. At least in my book, you'd have come out of this a lot better if you'd taken GP's advice and backed off gracefully one or two comments earlier.)

If your objection was to him having a too strong opinion, which would be more than welcome, you would be better served by making your argument relevant to that, and not geography trivia. It's a form of ad hominem, of which all forms are annoying.