Country X isn't just crying wolf to smear Y here. Y invaded a neighbouring country years ago and is again concentrating troops at the border.

And it still doesn't answer why the Russians chose to destroy a huge sat (more fragments) built by the USSR (more material to fragment) at a relatively high orbit (more time for fragments to destroy other sats). They could have done the thing India did and ram a small-ish sat at a low orbit and the fragments would be gone within a couple of months.

Instead they chose to even endanger their own cosmonauts on the ISS.