I'm pretty sure you know to what it refers and are just trying to make a point/start an argument. "American" is the only demonym of which I'm aware for a resident of the United States of America. Rarely (if ever) does someone require a demonym for residents of two continents, and I don't think I've ever heard someone use "American" to refer to a resident of "the Americas" outside of an irate non-American.
The article headline was more precise though ("Almost half of the U.S. population does not have a job"), so here editorialising made the headline worse in at least one respect.
The title was actually changed because a bunch of people thought it was sensationalized and sounded too close to a 51% unemployment rate (which isn't, "percentage of people without a job".) See here: https://news.ycombinator.com/item?id=23706562
Yes. The headline was changed for that reason, making it better in at least one respect (namely less confusing for people that do not know the distinction between unemployment rate and employment population ratio), and worse in at least one respect (replacing the specific "U.S. population" with the less precise "Americans"). As I said.
