Well, it's this trouble with labeling things.
The San Francisco electorate, by and large, would likely call themselves "very progressive", probably more so than any other major city in the country. Almost all of the significant power brokers, all the way up to the governor's office, in San Francisco politics would call themselves "very progressive". In that sense, San Francisco's government represents the one of the purest embodiments of what is a real political bloc or viewpoint or movement, one that calls itself "progressive", and what it might hope to achieve. Friedersdorf wants to call this politics "progressive" too; you object, and say this "American progressiveness", and the utopia created in its image to the best of its abilities, has little to do with "real progressives" and what their utopia might be like. But either way, I think what I'm trying to get at is - regardless of what you want to call it, it's real.
And I think there's something to be said for, "Conor Friedersdorf is an American, writing in an American magazine, about American politics" that makes it reasonable to highlight that distinction, or default to an American understanding of the term. I'm not trying to say that "Nordic progressiveness" isn't better than "American progressiveness", or that it isn't good or workable, but I'm hesitant to say that it's "truer" than "American progressiveness" - that's the fallacy.
(and, for what it's worth: highlighting a real distinction is certainly a rhetorical feint, and maybe a case of moving the goalposts, but it's not the same as No True Scotsman, where the distinction is, as Wikipedia puts it, "rhetoric [that] takes the form of emotionally charged but nonsubstantive purity platitudes")
But to be clear, I do like this reply a lot. And also to be clear, I'm Canadian, and in most respects like the way Canada is more progressive (in any sense, really) than the US, and think both of us would be better off if we were more like the Nordic countries. So I think it's valuable to ask, then: why is it that, Sweden, say, is more successful at producing good "real" "progressive utopias" than San Francisco?