I like David Graeber, but this feels completely made up and devoid of evidence. I mean... the "phallic" shape of a necktie is more of a byproduct of the tailoring of men's suits. Cravats and silk scarves don't look phallic at all. Plus, what kind of ties do cowboys and Texans wear, the swingin'est dicks of 'em all? Tell me a guy with a giant truck, a huge hat, ridiculous boots and mud tires is gonna wrap a tiny little leather thong around his neck if it's in any way a phallic symbol.
I wore a John Lennon bolo tie all through middle school and I can say with 100% certainty that I never considered it a phallic symbol in a tiny leather thong I'll have to find a picture of it sometime. It was a big part of my world back then. I resurrected it for my high school graduation day.