So, in your world, the US government is responsible to provide you with a detailed justification for the specific sanctions being applied against a foreign adversary? Keep waiting.

I really don't think you understand what's going on in the Russian economy right now. Russia has unwittingly gotten themselves embroiled in an existential conflict. (Less existential for the country than for the warlords running it.) Every expenditure or resources, natural, human, financial, etc, is being weighed against it's benefits to the war. Even basic things like their ability to feed their population are only valued because the war can't be fought without them. That's what a war economy is.

Despite all the failures of the Russian military, it took well over a year for Putin to fire his top general. The reason it took so long was that Putin trusted his general to remain loyal and not initiate a coup. Removing him was a drastic move, but the more interesting part is who replaced him. The new Russian defense minister got the job with absolutely no military training, background, or experience. His only qualification was that he is an extremely capable economist who is largely credited with helping Russia transition to a war economy and blunt the impact of western sanctions. That should tell you all you need to know about how important Russia thinks economics are to the war.

our work should exist for all mankind and to the betterment of society as a whole

That's nice and all, but totally unrealistic. The vast majority of kernel development is done because the developers (or their sponsors) benefit from the work they do and from having that work integrated with the rest of the kernel. I don't see that as a bad thing.

Ban work on Russian firmware or Linux compatibility with Russian hardware.

There is no such thing as "Russian hardware" when it comes to computing. Russia has it's own standards for a lot of technologies, but creating a proprietary set of computing standards that's disconnected from the ecosystem of western hardware makes no sense. They manufacture some of their own computing hardware, but it's all based on the same standards that are used everywhere else.

I would be absolutely amazed if the Russian government is somehow on the bleeding edge of linux development and actively deploying head branch builds of linux with the latest available firmware.

Why? Anyone contributing to the Linux kernel is, almost by definition, at the "bleeding edge of Linux development". It may not be the bleeding edge pushing the boundaries of computer science, but it doesn't have to be. A whole lot of kernel development is pretty basic stuff aimed to satisfy particular needs or requirements. Drones benefit greatly from highly specialized power management, real time data collection, flexible networking, etc. Most are built from off the shelf hardware and consumer electronics.

their almost certainly backporting to a stable linux release and that means this kinda ban if it follows you’re reason isn’t going to have an impact

The issue of drift exists with both older and newer kernels. If a particular kernel is so stable that drift isn't an issue, then it isn't a kernel that will be adding a bunch of new Russian commits anyways. If they are simply back-porting it themselves, then their inability to commit to the main Linux branches is irrelevant. In the scenario, the whole discussion is moot.