I agree that this definition is fuzzy. (So does Carroll, as he makes clear in the text immediately following the bit I quoted.) But no, I don't think it's moving the goalposts, though it may not be putting them where you would prefer them to be.

I take the basic arrow-of-time problem to be something like this: The universe appears to be dramatically asymmetric in time: it is expanding in one time direction and contracting in the other; if we trace its evolution in the direction we call "past" according to our best understanding of the physics, we ... (read more)