Homuncular theories, theories that are based on what goes on in my mind, never explain what it is to BE a mind, to BE an observer. They always assume an unexplained observer. That's the little man. Behaviourists agree with cognitivists about the unacceptability of a homunculus. They disagree, though, on whether ALL theories of internal representation require a homunculus.
Behaviourists think yes, cognitivists think no.
It is a mental state we all recognise, because we all have it. So what we want is an explanation that is not homuncular, that does not rely on an unexplained little man in the head, and one that is not animistic, that does not rely on our shared intuitive, introspective but unexplained understanding of mental states. That will be an explanation of the mind.