The variable CONSAD is controlling for, at least from my reading, is "people who have interrupted their careers by temporarily withdrawing from the labor force or switching from full-time to part-time work" -- mostly women who take maternity leave or part-time jobs to raise children. The amount of money those women would make if they hadn't interrupted their career is an interesting data point to determine, but I would argue that by using that "adjusted" amount, CONSAD has moved the goalposts, because that's not the median gender wage gap as actually experienced. The various studies linked to by the WaPo and the AAUW study all seem to be in general agreement around the 14-19 cents range. Whether that's "significant" is subjective, I suppose, but it doesn't strike me as a small amount.

Are we supposed to just unfairly give people the same salaries when one worked part time instead for 4 years?

If the starting point is recognizing that people have kids and it takes time to care for them, and both parents have that right and obligation.

From there, one could devise policies that encourage BOTH men and women to take parental leave and invest in high-quality childcare for when that parental leave is over.

Obligation? yes, right? not really

We're supposed to fairly reward two people the same for doing the same job. If you have more experience then you should have more responsibilities - that is what should increase your wage, not simply "time served".

Are we supposed to just unfairly give people the same salaries when one worked part time instead for 4 years?

Let's dig into that a bit.

Suppose Bob and Agatha are both working full-time at the same company as, for the sake of example, sales engineers, and they're both making $100K. Agatha goes on maternity leave, and afterward the company agrees to keep her on as a part-time sales engineer, working 25 hours a week at $62.5K.

If, after four years, she and Bob both apply for full-time senior sales positions, is it "unfair" for Agatha to be offered the same salary as Bob?

I feel like the better option would have been to split the difference with a female co-worker?

Good luck!