I haven’t gone through all their work, but some of the delisted maintainers were working on driver support for Baikal, a Russia based electronics company. Their work includes semiconductors, ARM processors. Given the sanctions against Russia, especially for dual use stuff like domestic semiconductors, I would expect that Linus and other maintainers were told or concluded that by signing off and merging their code they’d be personally violating sanctions.
Key detail: they’re not dropping it because they’re giving up, the judge dismissed it without prejudice, which means that in 4 years they can pick the case back up. Under a Trump DoJ the case would likely have ended with prejudice, closing it permanently.