to call someone by the pronoun that matches their gender expression, when their looks don't match it. There is, however, an economic component to that. These people are often doing the best they can with their resources. If they had the money, they'd probably take greater steps to make their physical attributes match their gender expression. So, to me, it comes to a point of compassion. They want to make their physicality match how they feel, but they most likely don't have the resources to do so.

Presenting is a part of the transracial discussion, because that's how race is is constructed, period. As I stated before, I don't know of any evidence of race being intrinsic. There have, however, been studies about gender being intrinsic. So, it's different in that it's not purely motivated by societal context.