That whole article reads so strangely.
I think the point they want to make is that gender stereotypes are bullshit (so girls can be strong! Boys can be sensitive! Who the fuck knew?!)
But that would make all their trans friends furious, so they've decided that gender stereotypes are brilliant instead, as long as anyone can apply them to themselves and then say they're that biological sex. If you're a sensitive boy, you're female! How progressive!