https://en.wikipedia.org/wiki/Francis_Bellamy
Francis Julius Bellamy (May 18, 1855 – August 28, 1931) was an American Christian socialist Baptist minister and author.[1] He is best known for writing the original version of the Pledge of Allegiance in 1892.
I think a lot of the classic rock vibe was about being anti-establishment, with little or no care for the actual ideas behind it. MAGA people see themselves as anti-establishment (despite, you know, everything), so it makes sense that a lot of the more superficial classic rock people would adopt it as their persona.