Why is this game so male-dominated?

Men are smarter than women. One has to only look at the world and see it. Biologically men are said to have bigger brains than women and the size of the brain equates to intelligence so that may be the most basic and empirical explanation.

That is plain stupid.

By that logic, the great whales are the most intelligent animals because they have the biggest brains. And we all know that isn't true since Douglas Adams informed us that it is actually white mice who take the prize.(somewhere in the Hitchhikers Guide series)

It's not necessarily stupid, just simplistic. In general I think there is correlation, but there are lots of other things that go into it, so you can't settle the matter just on size. Not to mention that intelligence is very broad and hard to define.

it requires brains not beauty

either men are smarter in terms of iq or close to no women play chess. I think it's because close to no women play chess since every chess tournament or club i've been to it's always almost all boys.

Women are smarter and have better things to do

what a stupid thing to write. imagine if i wrote that men are smarter. or that hindus are smarter. or that gay people are smarter.

statements like this are pandering.

yes, there are differences. trying to automatically accept everything where all minorities are somehow superior in every way does not work. equality means equal. 

a larger brain does not equal iq or eq, just as you wrote. it's funny how people think that a large brain equates to knowledge. maybe it's movies of martians with big heads that have influenced many.