What I got from it, while not a conclusive answer, was that because of the historical ban for anyone but the royal to eat swan, there is no tradition anywhere in the western world for it. Also people don't like to eat "cute" animals, like seals or squirrels. And lastly, when something is classified as a pest, people don't want to think of it on their dining room table.
While the article doesn't explicitly say the exact reason why, I think these were the main points. So I guess that is badly formatting on the article writers side.
But the premise is already weird. Who is "We" as in "Why don't we eat swans"? And who considers swans 'cute'?
I mean, I consider cats cute, lots of people consider dogs cute - and both animals are eaten in this world. Better example: Horses are cherished as companions and pets for some people and I _regularly_ like to eat them. There's even a dish local to the Rhine area in Germany [1] that (used to, it is replaced by beef quite often by now) is based on horse meat.
People tend to love dolphins. Asian cultures eat them. "They are cute" is not an argument here. That might explain a bias, but not why there's (according to the article) no swan to be found on any menu?
"We" would presumably be the types of people who read the magazine. According to the about, that would be:
"window-herb growers, career farmers, people who have chickens, people who want to have chickens and anyone who wants to know more about how food reaches their plate"
and given the staff members are all US oriented, it's most likely assuming a US readership and US food culture.
Thus we, who are random fly-by strangers to the magazine, shouldn't really criticize harshly when they don't take an unexpected audience into account.
While the article doesn't explicitly say the exact reason why, I think these were the main points. So I guess that is badly formatting on the article writers side.