Then they can also keep this accusation out of the public eye and deal with this on a diplomatic, which is where these kind of things should be (first) dealt with anyways (as least according to protocol). And this is exactly where so many political accusation lately go off the rails, because although most people are blissfully unaware of it (and hence make them good useful idiots to have the wool pulled over their eyes), these direct political attacks without presented proofs are very much against both the spirit and also the letter of the protocols for such situation.
I have to admit that in this particular case I don't know if diplomatic protocols have not been first exhausted before going public like this, but in many other cases that step certainly has been skipped/omitted. Which in themselves were pretty darn shameful violations in their own right. No, some people argue that it is warranted because Russia is doing wrong in the first place, which of course fully hinges on the assumption that the claims are valid in the first place (without any chance to verify this). However, nowhere does it say that such situations should null and void diplomatic protocols, so this line of reasoning is actually politicized hogwash.
> no amount of evidence would be enough or credible enough or good enough or acceptable enough etc
Where did you get that? If you know how this "game" actually works, you would know that at some level there will be matching/corroborating information coming from source that are not all controlled by the same interests (or group of interests). I've heard this (false) argument that it all comes don't to trust in whoever provides whatever evidence, but that just isn't true. With enough detailed information (which of course and conveniently is never given; should give rise to enough doubts on its own) it is most certainly possible to give a credibility to such evidence that goes way beyond just the credibility of the source of the damning details itself. I've personally seen cases where this was done, among nations that usually have different or even opposing agendas. But when it comes to (most) accusations towards Russia, the most striking part is always the total absence of any evidence at all. Since when have we become all this gullible, that we just believe organization who themselves have questionable track records on their good word and reputation?
Nah, that just doesn't cut it for me. For for anyone to whom it does, good luck with that unwavering faith (which in my opinion goes straight against logic).