i never thought of it as a homophobic insult because plenty of straight bi etc also suck cocks, if ive ever heard cocksucker in a homophobic context ive always heard a certain slur right after it

to me, cocksucker reminds me of a prison dynamic, where its more about the power of making someone suck your cock vs them being just gay for sucking cock

but at the end of the day it dont matter we’re all just arguing about an insult homophobic or not i dont think its a good use of our time to continue to argue about its semantics