as to the maxima and Mathilde....
I think they are pointing out the difference I. She and background. Maxima was 28 when she met her husband. And though her dad was in politics, she lived a pretty simple middle class life. On the other hand Mathilde was 23 when she and Philippe began. At that age she years is a big difference. She was alsp raised in the minor aristocracy. She may not have been raised to be a queen, but she wouldn't have been new to these circles. She would have had a better understanding.
Wasn't Maxima's father a wealthy landowner ? I am not familiar with her family, but Argentina is a fairly large country where rural properties tend to be much bigger than the most impressive estates in Britain or France, and even more so than estates in the tiny Benelux countries. As far as Argentinean social hierarchy is concerned, I would suspect then that Maxima was much closer to an equivalent to "landed gentry" than to a "quiet middle-class life". Having said that, I agree that Mathilde, having been born and raised in Europe in a very old aristocratic family, probably had a better understanding of royal court life than Maxima had when she married Willem-Alexander.
On the broader discussion, one cannot ignore the historic background. When the (mostly Protestant at the time) Republic of the Seven Provinces seceded from the Habsburg Netherlands in the 16th century, the Catholic south that is now Belgium remained under Spanish and, later, Austrian rule (when the Spanish branch of the Habsburg family became extinct). Following the occupation of both Belgium and the Netherlands by the French during the Napoleonic era, the Congress of Vienna sought to create a United Kingdom of the Netherlands under Willem I of Orange-Nassau. That united kingdom lasted 15 years or so only, as the Belgians rose against the king in 1830 and established an independent kingdom of their own whose crown was offered in 1831 to Leopold of Saxe-Coburg and Gotha.
The Belgian revolution was triggered by (at the time) irreconcilible differences between the South and the North over language, religion and the constitution (Willem I having in particular absolutist tendencies, whereas the liberal Belgians wanted a more limited constitutional monarchy). Of course, the context has changed over the past 200 years and Belgium and the Netherlands now enjoy very cordial relations within the European Union, but historic baggage cannot be erased and surfaces occasionally in articles like the ones linked above. Let's not forget that, until today, Belgian law, I believe, forbids any prince or princess of Belgium from marrying a member of the House of Orange-Nassau, reflecting perhaps lingering insecurity over a Dutch annexation of Belgium.