Well, Meta.stackoverflow really us meta.stackexchange (go there! meta.stackexchange.com). For historical reasons, meta questions for the whole site were shunted there, and splitting off a SO specific MSO from the site proved difficult. It may happen eventually though. MSO/MSE is pretty much a standalone site for asking network related questions.
I'd also note they have a different community culture and attitude towards reputation - bounties are often used to draw attention to a question (even if occationally there's no answer to them). There's also some wierdness (like confused folk posting SO questions on MSO), and such.
The simple answer, really is MSO is a wierd beast, and its a SE site about SE as a whole, rather than a support site as the metas are. It just works differently
