FWIW, as another anecdatum from an American, I was always taught the "British style" was the correct way, and the "American style" was incorrect. They were never referred to as "British" or "American" though, just "correct" and "incorrect".
I prefer the "British" style, FWIW. Maybe it's just what I was taught, but I have encountered arguments for the other way periodically (causing me to have to check), and I always preferred the way I learned for the reasons in the article.
the "british" style also introduces an ambiguity. Did the original quote contain the puncutation, or does it derive from the outside context?
It's pretty clear to me that the correct method (on the grounds of respecting source material) is: "punctuation inside, if it comes from the source, punctuation outside if it's from the outside context".
And there are times when quotes aren't even direct quotes, they could be scare quotes. Why the hell would you ever put punctuation inside of a scare quote? I don't think any american would do this.
E.g.:
Dough is pronounced like "doe." -- TERRIBLE. Stab my eyes out.
I prefer the "British" style, FWIW. Maybe it's just what I was taught, but I have encountered arguments for the other way periodically (causing me to have to check), and I always preferred the way I learned for the reasons in the article.