Why is every country in the world male-dominated?
In what way? There are many ways to dominate the world and other people, as well as dominate someone’s personal world.
In terms of money, business, politics, military conflict - yes. And men do tend to be more ruthless, risk-taking and obsessed with bottom line over common sense in these areas which isn’t a good thing.
In science - also yes, but in science it’s of no consequence. They’re looking at things objectively.
In personal relationships, family, romantic love and sex, child-rearing - no. The world is dominated by women, they hold much more power and sway over men than the other way around.