I feel like the simplistic representation is the right one here.

Women are earning less on average due to a multitude of reasons. Some are an issue, some are not. Who is to decide which reasons should be accounted for in this percentage and which ones shouldn't?

I have seen plenty of statistics where they calculate the percentage down to the immediate difference between men and women in exactly the same positions with exactly the same experience levels. But that removes the very crucial fact that some positions simply aren't equally accessible to women, even if the ones who make it in do get a fair pay compared to their male peers.

It's like comparing a newbie and a senior by median pay and claiming they should be paid the same because they are human.

I'm not going to engage in the typical internet "Oh so you're saying ...!" thing, but damn, read that sentence again and think about why it might not apply to this situation.