I find it very weird that such organization is allowed to maintain its sovereign status. Other organizations should be able to be sovereign too if this is allowed.
To keep things fair and equal, all that is needed is that other organizations are able to maintain their sovereign status in the same way the Knights Hospitaller did. So the path forward is clear for the other organizations you have in mind. First, gain the recognition of the Pope or some other sovereign entity. Second, spend centuries conquering and holding on to territory with the backing of this sovereign. Third, declare sovereignty and have it recognized internationally. Your organization is now ready to let go of its territory and if it manages the diplomacy just right, it can perhaps maintain its diplomatic relations and sovereign status.
That appears to be an autonomous zone allowed to make its own rules but still under the sovereignty of Greece. Also it looks amazing but I'm bummed I wouldn't be able to visit as I'm female (though I respect the tradition behind it.)
> other organizations are able to maintain their sovereign status in the same way the Knights Hospitaller did
Which is really easy for them because they're really friends with the powerful psychopaths running our planet. Most communes have been either assimilated or destroyed by the colonial powers that be.
See the ZAD in Notre-Dame-des-Landes or Exarchia in Athens for some of the latest examples of State power colonizing areas they had previously been consciously chased away from by the local population who just wanted independence from tyranny.
> Other organizations should be able to be sovereign too if this is allowed.
Many people have tried over the years. But only those that play nice with tyrants are allowed to survive. Hell even entire nations who did not bend to the wills of their colonial masters of yesteryear have been meddled with. See the assassination of Thomas Sankara (a democratically-elected president) as example of the dozens and dozens of US/Europe-powered coups d'État of the last decades.
Autonomous communes, whether squats or private property, have tried to declare their independence for centuries. The truth is they've been either assimilated or destroyed by Nation States. There's a very nice/powerful movie called La Cecilia about that.
The SMoM was a useful entity for NATO when it came to the Cold War. Italy was forbidden from operating a large airforce under the settlement terms. The SMoM allowed Italy to field a much larger airforce than it would have otherwise been allowed to.
It is allowed because the Order effectively predates the nation state as we currently know it today, and it is influential with one of the largest and most influential non governmental organisations ever, the Catholic Church.
I suspect there was some diplomatic gymnastics at play here which permitted the Order of Malta to be used this way, perhaps those two examples did not want to involve themselves so openly in the Cold War. I am just guessing at this stage.
It's 'sovereignty' is purely at the mercy and whim of real nations. The fact that it is basically a social group for the aristocracy is honestly the only reason it still exists.
"Aristocracy"? I am fairly sure that an acquaintance is a member. He is an American of Irish descent, meaning very likely a descendant of half-starved peasants who emigrated 170 years ago. My impression is that an American gets into the Order of Malta by giving large sums of money to Catholic charities, and perhaps other Catholic causes.