Wenqin is very acute on grammar, while hammerheadshark is thoughtful.
I guess there existed different perspectives among the people who read this article. Some people might think it was just a narration of one of the author's life experiences, while the others might have taken the writing as a fun-making joke. It is this differentiation that created a difference in the opinions of using the two words and the two articles.
In case you thought it was just an account of an experience, you might have neglected some particular considerations the other category of the reader have paid attention to. In order to make the story funny, some particular words need to be used to bring out the maximum dramatic effect that is desired.
So now if you believed the article was a joke, you may have noticed that the joke is based on the following 3 fun-making elements:
1) The "author" sensibly thought that he finally defeated the talkative guy in the small talk he is not good at, but the truth is NO. He successfully drove mad the talkative guy merely by his insensible use of the terms "Parkistan Chinese" , and "Canadian Parkistan Chinese", not by his use of "quick wit". As a matter of fact, the author was supposed to have used the correct terms like "Chinese Parkistan" and "Chinese Parkistan Canadian"to otherwise make some sense。This is truly a smart design for the joke's funniness.
2) The use of "understandably": he smiled understandably, meaning that he was dealing with the situation in a funny way, it is an indirect way of expression, the chinese counterpart of this word is (你懂得的方式, 你懂,無需多言,haha 狡猾狡猾的). Understandingly means 會意地. This word is perfectly acceptable being used there if you think the writing is just a general narration, it, however, delivers less air of humor in the other case.
3) a, the, and nothing there.
Grammatically and humorously, there should be "a" overthere. For humorously alone, it seems that nothing there is better:)))
Conclusion: none is wrong in terms of the agreement between the opinion and the perspective.