John Walker, at first introduced as an unwanted new (and as far as fans were concerned, fake) Captain America in the latest MCU series, The Falcon and the Winter Soldier, has quickly become one of the villains fans love to hate, thanks in no small part to Wyatt Russell's nuanced portrayal of the slowly unraveling pseudo-hero.
Despite his undeniably heinous acts, though, his story is ultimately a tragic one, reflecting the experience of many soldiers chewed up and spat out by the American military for doing what they wanted in times of war. His wartime service, which appears to have given him serious PTSD symptoms, was lauded by the government - though it's heavily implied in his conversation with Lemar Hoskins, aka Battlestar, that he did terrible things to be awarded his medals of honour.
It's fair to say, then, that it's more than likely that the American government had no objections to Walker's murderous actions in Episode 4 - only with the fact that it was so public, more interested in the optics of Captain America killing a man in cold blood than the morality of it. Especially a Captain America that was obedient to the US government in all the ways Steve Rogers never really was, despite his iconography.
His words during the trial rang eerily true; about how the American Military made him, how he only did what they asked, acted under their mandates, did his job well. He had been rewarded for the same actions that he was eventually condemned for at the whims of his superiors, reflecting the experience of many soldiers simply "following orders". The fact that he was seen as a "fine soldier" reflects how "fine soldiers", both in his story and very often in real life, are often easily manipulated due to their obedience...