The author doesn't take on that issue head on, because its focus is more on terminological precision, but it does hint at an answer.
> National identities are, after all, not merely about inclusion but also about exclusion
> the nation is an exclusive identity, but citizenship co-exists more easily with other identities
Calls to nationalism are often not so much calls for unity as they are calls for exclusion of or opposition to some "other" who does not share that nationality. This is not necessarily a bad thing. When it's a minority nation seeking independence from a larger state/empire (e.g. Scotland from the UK) it can even seem noble. When it's a powerful nation seeking to exert its will over other "lesser" nations (e.g. Russia in any of its imperial/Soviet/current forms) not so much. In general, "nationalism" has negative connotations, is part of the standard definition of fascism, etc. "Civic" identity (what the author suggests the US actually has) is generally more positive and supports more humane policy. To the extent that words matter in general, this one certainly does.