So what does this really mean? That a majority did not ask for payment?
No, I'd guess that it means that the majority did not ask for payment
above that necessary for survival. There's the "slavery" way of doing that, forcing people to work and merely pay them the bare minimum to survive (the 19th century treatment reserved to industrial proles, too), and then there's the "motivation" way, paying them that necessary minimum and then offering an extra for satisfaction in some intangible form: partial ownership on what's being built, decision power, religious motivation, whatever people are willing to take.
High wages, material rewards, are just one possible motivation among many, even today, even in capitalist economies. And even the people who demand them may be doing so more because they use high wages as a way to keep tabs on how well they're succeeding than because they're actually going to spend it all.
So I don't think that Hitler and Stalin being military imbeciles necessarily suggests that other powers were lead by those, too (if I understood you correctly).
Ok, granted. And France's high command did make some big mistakes, too.
I never really got that to be honest.
If a country has a strong export surplus, it is more concerned with producing goods for other markets than for the own one, this is perfectly sound. But what happens to the money earned by doing that?
Where's the money? That's a very good question, and one which, I am sure, people should be asking more often!

It depends on the circumstances.
If a strong export also pours a lot of money into the country, which is received by the people through wages / payments, shouldn't they be able to consume just as much as if the companies earned the money by producing for the domestic market?
Now obviously, if this were the case, you wouldn't have an export surplus anymore, because then the purchasing power of the domestic market would have to be satisfied by more imports which would eventually balance the export-import-relation again.
So I ask again: what happens to the money? How can such a imbalance form in the first place and why only in countries with high exports?
Or to summarize: Why does a strong export not stimulate an equally strong import?
It depends on who receives the money, on how the profits from exports are distributed inside the exporting country. Does it get distributed among the mass of workers, as wages, or are most of those gains distributed by the companies as profits or retained for reinvestment?
If distributed as wages then people will either save or consume. Because people will not save indefinitely, what you assumed above makes sense, imports will tend to balance exports.
If distributed as profits then it seems likely that the most wealthy will benefit disproportionally, as they'll have bigger ownership stakes on the companies than your average worker (if he has any at all). And because there's only so much that an individual can consume, most of those profits captured by the wealthy will end up reinvested (or, during economic crisis, stashed away in idle bank accounts or other forms of idle wealth), not spent on consumer goods. A strong indicator that this is happening is a positive trade balance for the country, with the profits from exports showing up in the balance of payments as a capital balance (loans to and investment in foreign countries and institutions). But it may also mean an unusual tendency by workers to save instead of spend, with banks exporting those savings in the capital balance.
If reinvested, then the average trade balance will more likely be null. Gains from exports will be used for buying capital goods from abroad, instead of consumer goods. Part of the investment will create internal demand, from suppliers inside the country, and that will filter down to either wages or profits, one or the other of the above scenarios.
Take the USSR quick industrialization as an example: it had to import industrial equipment and technical expertise. It had to pay for it, because no one was going to borrow them money. So it had to export whatever it could: production efforts had to be directed towards export goods, not consumer goods, and those goods actually exported in order to pay for the material necessary for industrial development. I won't say that this justifies the recklessness of Stalin's economic plans, but it explains why the needs of the population were regarded as a secondary concern by the planners. Because the economy, those state companies, was "public", it is believable that some
of the workers would voluntarily accept those conditions: in capitalist economies doesn't the small businessman tend do sacrifice his own consumption in order to put aside money for investment? Workers, as owners of state companies, were being asked to do the same... though they didn't seem have been given any choice!
Or take what seems to be the current China approach to industrialization: it combines exports and low wages, with the wages kept low simply through the use of a huge pool of manpower - competition among workers for the sale of their labor. Certainly a more capitalistic approach! And other countries have been known to keep wages low deliberately, by attacking attempts at unionization (for example, I still recall the frequent news about clashes in South Korea, though those seen to have mostly ended, and wages risen), by giving all possible state support to large monopolistic companies within the internal market. These countries seem to have a plan of channeling the profits from exports not to workers, for consumer spending, but to the companies, as capital to be reinvested. It's the same process as the USSR's to drive industrialization quickly, except that the companies are privately owned instead of state-owned. It may make it a little more difficult to persuade workers that they too are benefiting from the economic development...