https://www.loudersound.com/features/story-behind-the-song-blitzkrieg-bop-by-the-ramones
“There was a big hit by the Bay City Rollers at the time called Saturday Night, which was a chant-type song,” says ex-drummer Tommy Ramone. “So I thought it would be fun to do for the Ramones too. And somehow I came up with ‘Hey! Ho! Let’s go!’ I just liked the term because it made fun of Mick Jagger singing the Stones’ version of Walking The Dog, where he goes ‘High low, tippy toe’. We all used to goof on that and sing ‘hey ho!’ instead.”
...“The original title of the song was Animal Hop. [Bassist] Dee Dee came up with Blitzkrieg Bop because he wanted to Ramones-ize it. And he changed one line. It used to be ‘They’re shouting in the back now’ and he rewrote it to ‘Let’s go shoot ‘em in the back now’. This might have led to the conspiracy ideas, but they’re not the original lyrics of the song. Dee Dee came up with the title and that line, but the rest of it is mine.”
https://nightswithalicecooper.com/2020/06/10/blitzkrieg-bop-the-ramones/
Despite the military connotations of the title, the song itself is actually good, clean fun, according to the late Joey Ramone. “I hate to blow the mystique, but at the time we really liked bubblegum music, and we really liked the Bay City Rollers. Their song ‘Saturday Night’ had a great chant in it, so we wanted a song with a chant in it: ‘Hey! Ho! Let’s go!’ ‘Blitzkrieg Bop’ was our ‘Saturday Night.’”