If the pay gap which persists between men and women was because they were paid different amounts for doing the same job it would be something to worry about.
But when you get part way through the story there is a sentence which explains it all:
A trend for more women to work part-time is often cited as a reason behind the pay gap.
Well yes. If women, or any other individual or group, got paid a lower rate for doing the same job there would be something to complain about. But unless I am misreading the information the stats aren’t showing that women get a lower rate, they get less in total because they work fewer hours.
There is nothing unusual in that.