Is it offensive? Well, maybe, but that's tact. However, is it true? Bear in mind that an excessively gregious society, and yes there are differences in societies, cultures, might view a more reserved culture as such.
And the real reason I'm responding is, how many "people there are on the streets" is irrelevant, in terms of being 'social' or not. People going places != social. It can equal work, needing supplies, traveling, etc.
I grew up in a small town, population < 1000, in a massively large county (>1000 square km), with barely 15,000 people in it at the time. When I first moved to the city, I would walk down the street and wave at people. People reacted, to my perspective, quite oddly. Some actually shied away, others looked at me as if was a lunatic.
Yet where I grew up, not waving would have been beyond rude. In the city, it was seen as absurd behaviour.
I guess what I'm saying is, Sweden could be quite anti-social, without it being "mean" to say so. It's all perspective.