I obviously can't see the original comment. But though being labelled a communist might be like calling someone a nazi in general American culture, some people freely identify as such. Klabnik doesn't seem to have a problem with that name, in fact.
> I find that perspective strange. Machinery does not particularly care what end it's put to.
Well it's a human activity like anything else. The technology itself might not be "political" [though that's debatable], but the attitudes and views of the practitioners will colour everything surrounding it. And Klabnik has shown that he has a big enough personality to impact the communities that he chooses to involve himself with, for better or for worse.