Real answer: he was a big asshole who got things done and said good words and occasionally did good deeds regarding the common people and he was so long ago most people don’t know the intricacies and can just kinda go with a vibe check, plus he predates the modern party identities so he can be whatever their imagination needs

Joke answer: because he was a big porkchop of a man with a bushy mustache but the tiny glasses made it funny, kinda like the tall man in the tiny car scene from the Simpsons