I get what you mean, Giovanni.But I don't necessarily understand...

I get what you mean, Giovanni.
But I don't necessarily understand the political/environmental rationale as per the link provided.

As I see it, the ships are built and now already deteriorating wherever they may be held. Whether they are broken up for recycling or not, the contaminants/toxins are leaching out due to deterioration. The leachate has to go somewhere in the ground and eventually into the surface and underground waters. So why not use ingenuity, creativity and technology to remedy the problem?

We get a similar situation when ships are regularly maintained in good functioning conditions, too. The heavy duty materials used in repairs and maintenances are the very ones that will in future produce contaminating/toxic leacheate when the ships are decommissioned.

Atlas Magazine tells us that as at 2023, the world has a fleet of 106,000 ships, which include general cargo, container and other vessels (presumably military ones as well).
The UK Govt. tells us that of this total, 68,000 are trading ships with a total deadweight of 2.2B tonnes. Let's assume that the military ships have the same deadweight tonnage. So the total available recyclable material is 4.4B tonnes. That's a lot of economic value contained therein.

The insurance statistics tell us that an average of 60-70 ships sink annually, presumably again from accidents rather than from decomissioning because it pertains to insurance. These ships would not be recovered from the seas and oceans. Their toxic leachates get diluted (not denatured) over time by the voluminous waters and carried by currents all over the world. Just like the continent-size amount of micro and not-so-micro plastics floating in the Pacific Ocean.

China, as the world's largest steel producer, produces approx. 1.0 billion tonnes of steel annually. The environmental effects of mining for Fe, Ni, Mo, Mn and coking coal, subsequent shipping to China for steel manufacturing would be massive.
In this context, the recycling of decommissioned ships (plus adverse environmental effects) again seems urgent because its total deadweight tonnage is 4x China's annual steel output. Of course, not all the deadweight is solely marine steel, which has approx. 10% Ni content. But marine steel is the heaviest material onboard the ships. So maybe 75% of the deadweight is marine steel?

It is fully possible that I'm missing some imporant considerations that favour leaving the deteriorating ships alone rather than to use our ingenuity, creativity and tech to recycle and in so doing clean up a bit of the environmental mess humans have created.

Speaking of the environmental mess humans create, I once read an academic paper that brutally argued why certain funeral customs represent the final insult to Mother Earth. Even after human death, some human practices will go on to pollute, by creating leachates from coffins (lacquer, lead, plastics, chemical preservatives) that percolate 6 feet and more into the earth and will take decades or centuries to decompose.

Not a nice closing note for the weekend. My apologies.