Actually I saw an interview with Robby Robertson that said the song was at least partially inspired by a great admiration for many of the Southerners he met thru the great Levon Helm.
Now as a musician I can tell you this: Your stories change with the audience.
I’ve seen at least 3 different explanations by Paul McCartney of the song “Blackbird”.
Of course I’m not saying there isn’t an anti-War sentiment to the song, but in the interview Robertson was very respectful and sympathetic to the people who hold on to their southern pride.
I agree. It's respectful to those who served, while expressing Virgil's disillusion in the cause, IMHO.