> A pro photographer and my mom will get wildly different results even with the same equipment. Not so with AI, which very much has it's own bias and is eager to inject it.

That particular AI models have their own bias and are eager to inject it is among the reasons why a skilled user and an unskilled user will have very different results, not a reason why that isn’t true.

> The other question is, is AI a tool or a medium?

Is oil paint on canvas a set of tools or a medium? In art, a tool ot set of tools often characterizes, or even defines, a medium; they are different but not orthogonal concerns. (And the cultural phenomenon of identification of a regularly-used tool or combination of tools as defining a medium generally only happens well after that tool or combination has been in significant use for a while.)

AI is a broad category of tools. Particular combinations of those (either with eachother or with other tools) may also come to be be understood as particular media.