I knew someone would trot that out. It's not what I'm getting at.
I said that women have a hard time getting jobs equal to men, not that they aren't being paid as well as men when they do (although even this is occasionally untrue -- there are some actresses who'd beg to differ, for example). Think about boy's clubs where men tend to hire other men; think about ostracization and harassment that push women out of roles prematurely; think about girls being discouraged from entering STEM programs because they're supposedly not as good at math and science as the boys. And of course, think about having to settle for a lower-paying job to support a new child.
Also, you do realize that you're treating male biology as a default, right? You gripe about women wanting more healthcare and more flexibility than "other workers," but who are these other workers? Oh, right. Men to you are the norm, and all women are outliers. I'm sorry, but if you really believe women are equal, you accommodate their biological functions -- you don't act as if pregnancy and menstruation are strange occurrences, or that it's somehow fine for women to assume they'll take a pay cut the moment they start a family.
This is true.
And I really don't care about a cafe in Australia (though, in passing, I wonder where the 18% surcharge ends up...does it effectively lower the prices for the women customers or does it just become extra profit for the cafe owner? The spirit of the idea would surely mean it ought to be the former, while the latter doesn't seem right - "help gender equality by giving extra money to one business owner who happens to be a woman"...or they could just donate it to women's refuges or such like, which would avoid that problem).
The only thing about the pay gap figure that bugs me a bit is you don't often seem to hear the same statistic calculated the same way for other forms of disadvantage. e.g. how much less a black person will be paid than a white person, or someone from a poor uneducated background vs someone born to elite parents, etc. It only seems to be for gender that the stat is quoted frequently.