It's not entirely true that the Dutch are always honest and direct.

I think that the real key to Dutch etiquette is efficiency. If it makes things go faster, it's good. You hold a door open for someone (irrespective of gender) only if it's efficient for both of you to do so. Directness is more efficient than beating around the bush, honesty is more efficient than a comfortable lie when it concerns an issue that's going to have to be dealt with at some point. Picking fights with people is not efficient. That's a waste of everybody's time.

> when you say something in a business meeting that is not a very smart suggestion, people will always point it out,” he said.

Because it's inefficient to waste time on a stupid idea.

> “You don’t talk too loudly on the train because it’s not too nice for the people in your compartment; you don’t
> play your music too loud in your apartment because it’s not so nice for your neighbours; there is this constant
> calibrating of your own behaviour,” Coates explained. But in the Netherlands, there is “the sense that people
> have the right to say whatever they want and be as direct as they want. And if other people don’t like that,
> it’s their fault for getting offended.”

I disagree. Most Dutch also don't talk loudly on the train. In fact, the Dutch are pretty good at minding their own business and ignoring whatever other people are doing. Bothering other people with your business is wasting their time. Of course jerks exist, but excessive noise is usually not appreciated.

> One time, I found myself at the supermarket staring with disbelief at the groceries that had spilled out of my
> hands onto the floor. Within seconds, I was surrounded by no fewer than 10 Dutch people, all of them giving me
> advice on what to do. But not one lifted a finger. To me, the situation was obvious: I needed help immediately.
> But the Dutch saw it differently: unless I specifically asked for help, it probably wasn’t necessary.

This may actually be a case of politeness. Maybe you've got everything under control and are perfectly capable of picking up your own things. If not, people stand ready to help, but if you don't ask, they will assume you don't need help. They don't want to intrude on your business unasked. Unless it becomes obvious that you do need help (but the Bystander Effect can be strong).

> “Calvinism dictated the individual responsibility for moral salvage from the sinful world through introspection,
> total honesty, soberness, rejection of ‘pleasure’ as well as the ‘enjoyment’ of wealth,”

Yet the Dutch do like to relax and enjoy themselves. We're world champions at part-time work, and hate the 50-hour weeks that Americans too often work. In fact, I don't think any country in Europe works less hours per year than we do. We don't want to waste time on silly nonsense, unless it's silly nonsense that we enjoy.

Though if there's one taboo, it's definitely conspicuous displays of wealth. Millionaires better pretend they're normal people like the rest of us. We've always been a very egalitarian society. Even in the 18th century, our transport network of river barges transported all passengers in the same cabin, whether they were nobility or peasants.

> This straightforwardness is so intrinsic in Dutch society that there’s even a Dutch word for it:
> bespreekbaarheid (speakability) – that everything can and should be talked about; there are no taboo topics.

Not entirely. A topic can be "bespreekbaar", but it's technically also possible for a topic to be "onbespreekbaar": not up for discussion. Usually, people tend to want to make things "bespreekbaar", because that enables honest discussion and more efficient sharing of information, but there are exceptions.

> Many of the older houses in the Netherlands have big windows, allowing visitors – if they so wish – to peep inside.

But it's rude if you actually do it. Many houses do have curtains to create privacy, but even if they don't, it's not okay to go peeping into other people's windows. That's intruding on other people's business again.

> “You sit in a restaurant with a friend and they will happily, in a room full of strangers, talk quite
> loudly about their medical problems or their parents’ divorce or their love life. They see no reason to
> keep it a secret.”

If it's something they want to discuss. If the topic needs to be addressed for whatever reason, they address it.

> “We don’t discuss salaries, we don’t discuss pensions. Anything to do with luxury. We don’t talk about how
> beautiful our house is. We don’t discuss how big our car is,”

Not quite. Conspicuous displays of wealth are not done. Showing off a nice house is totally fine, as long as you don't present it as evidence you're better than others. Salaries used to be taboo, because differences in pay smell of class differences, but that's changing, because clearly salary negotiations are more efficient if you know what your coworkers get.