"It's true their average speeds are much slower than American roadies and that in itself may be the real reason."

Ammond, I think you got a good start on answering your own question/argument. Amsterdam is wall-to-wall people and then some, a relatively small city with New York density (and the 84 square miles in the Wiki page must be including some of the less dense satellite areas like Bijlmer, because the more touristy bit, which is less than 30 square miles, is really jam packed.) It's crammed in every way, so speed is not really possible, and there's only a little way to go before you're in the next city. And when you're not going anywhere to speak of, speed is not essential.

When they're out in the country - or, more precisely, what they would refer to as the "country" - I never saw anything that looked like real "country" as it's hard to find a spot out of clear sight of the next town - they may sometimes even ride road bikes and even wear your horror of horrors, spandex shorts. (By the way, I've never quite understood the horror of some over those, in the light, or whatever it is, of the routine acceptance of the often glossy spandex, or at least spandex-like, knickers that are part and parcel of the standard American football uniform.)

In addition, theft is so utterly out of hand that you can't use an even slightly decent bike for utilitarian purposes unless, for example, you commute and can take the bike inside where you work. I knew a couple of people who could indeed take it inside, and they indeed rode road bikes to work unless they needed to run errands (they also participated in races, so sport and utilitarian use are actually compatible, contrary to what you seem to imply.) So it's a choice forced by social mores, in this case that people profess to hate petty crime but fundamentally condone it as some sort of Robin Hood thing. That means we can't know what they would do if they could choose freely.

And then there's weather. On the exceedingly rare occasions when it hits 90F in Amsterdam (all-time record a whole 93, something I, even well in the north, can only wish for), it now makes for global headlines about how, boo-hoo, the world is coming to an end. In many parts of the USA, spring and fall are short, leaving little time when it's not (1) too icy to ride safely, or (2) reaching well into the 90's F or at least the high 80s and probably with a sky-high dew point. In that kind of stifling heat, virtually unknown in Amsterdam, one's office mates will simply not tolerate one's failure to wash up and change clothes unless the distance is very, very short (see first point above.) So, might as well wear something that's comfortable on the bike, rather than lug all sorts of heavy fenders and guards up and down hills in the heat in order to accomodate flouncy clothes one will need to change anyway. (Another alternative is the Tokyo-area approach, to carry, at a minimum, several freshly washed shirts or blouses to change into every couple of hours over the course of a perfectly normal steaming, sauna-like summer day.)

Oh, and I was forgetting the ultra-flat terrain of Holland, which beats out by a long shot many areas in the allegedly flat U.S. midwest. I wouldn't care to try to get the perfectly normal $20 single-speed Amsterdam junker bike up and down the hills of San Francisco several times a day, or up and down Midwestern hills in the heat of a 95F early evening commute (heat aggravated by our corrupt Congresscritters with their Daylight-Saving Time.) But then again, Amsterdammers never need to - the highest terrain for many miles around would be the motorway overpasses.

As to the helmet issue, well, with respect to smoking and leaded gasoline, Europe lagged fifteen or twenty years behind the USA. So I think the jury is very much still out on what the 'elf'n'soifety Puritans will forcibly impose in Europe, as they have all long since run out of important things about which to get their undies all in a bundle. Stay tuned.

In summary, while I'm aware that a very peculiar national self-hatred seems to be de rigueur among many leftists and environmentalists in the USA, when all is said and done, it is not terribly helpful always to view things in snarky terms ("We think it's just for sport. Cyclists in Bruges and Amsterdam think of it as life.") based on apples-to-oranges comparisons that fail to compare, and fail on no less than multiple physical and social dimensions.

Ammond,

As PaulS's reply illustrates, often there are rational reasons having to do with different local conditions as to why different cultures have different practices. The Americans who look down on their fellow citizens as somehow morally defective as compared to Europeans ought to try thinking before snottily condescending. I realize that makes it harder to score status points. But it leads to a more accurate assessment of reality.