I recall that it was played at Winston Churchill’s funeral (2:30) in recognition of his American mother.
In colour 
if anyone’s interested: Sir Winston Churchill's Funeral: A World In Remembrance (1965) | British Pathé - YouTube
It’s a battle hymn. You were expecting it to be kind of chill and woke?
Psh. My favorite from that era is the Maryland state anthem, which was written about anti-Union mob riots in Baltimore.
Or try any of these:
Wow. Jabba the Hutt would comment, “My kind of scum.”
Of course you recognize the tune–it’s “O Tannenbaum.”
I remember learning that one in 4th? grade while my dad was stationed in DC for a couple years.
“The Despot’s heel is on thy shore,
Maryland, my maryland
His torch is at thy temple door!
Maryland, my maryland.”
I couldn’t sing it without giggling.
Parodied at the time, by Union supporters and soldiers, thus:
“The despot’s feet are on thy shore,
Maryland, my Maryland!
I smell 'em half a mile and more
Maryland, my Maryland!”
My father, a lifelong atheist, has asked for that song to be played at his funeral.