It's not surprising that Germany is lacking these supplies as their military procurement is... incompetent, or rather, it's a complex web of insane bureaucracy, poor decision-making, and political interference, all under the understandably long shadow of two World Wars and the Third Reich.
But the Leopard II is a hugely popular export model, so I'm a bit surprised that they can't source parts for repair from NATO members and other allied countries that operate it. Many of which have their own licensed domestic production lines and supply chains to support them.
That's not what's happening here. If anything, this the US flopping it's massive dong on the table and asking if anyone else wants to prove they can dick her down good enough to take over.
The post-WW2 global economic order is built on the security guarantee that maritime trade is secure because the US Navy will fuck anyone's shit up who uses force to interfere with it.
Ironically, the biggest benefactor of this arrangement has been China. That's also who would be most impacted by long term closure of these particular maritime routes.
So knowing that only the USN is currently capable of providing the long term security guarantees for this situation, they are going to make a show of it, or extract something of value their efforts - even if it's just countries voting for some UN resolution that goes against their public statements or political rhetoric.
Please understand that this explanation isn't my personal endorsement, approval, or disapproval, of what's happening, or why, it's just a very high level statement of facts and neutral analysis on the situation.