I can't believe I signed up just to explain this. An Oxford Comma is the optional comma before the word 'and' in a list. Many people care about this stuff (trust me, I'm friends with many of them). Actually people argue about weather or not an Oxford Comma should be present. Many people are strongly opinionated. He's saying "Who gives a fuck...?" The whole song is about how people are too focused on stupid things. Ironically we're all sitting here debating about the stupid things he was talking about. The 'Oxford Comma' and the 'Oxford Climber' represent all the stupid things people care too much about (like the meaning of the song--who cares? Just enjoy the song).