Why would a former US army sniper have interesting insights into war in Ukraine? Unclear on both what a sniper’s perspective would bring to the discussion and why US army combat xp would be relevant to a war where the US army is not deployed.

Because he has recent combat experience, and therefore better tactical experience than the average Russian soldier. Also because the US army is less hierarchical and top-down than the Russian he has more operational and strategic insight. He filets the Russian army, with precision.