But, as someone pointed out earlier, the mountain is a more unusual example of his gender (and species) in terms of strength, so he does cost more.
The DnD stats system is based around paying more for having extremely good stats.
Just like in the real world - a woman can run the 100 meters in 11 seconds is in the 100m final at the olympics, a man who runs 110m in 11 seconds is just a fast guy. We celebrate the woman who runs the sub 11 second 100m because she is a more unusual example of her gender than the man who can run the sub 11s 110m. Indeed, she costs (and makes) a lot more than a man of equal speed to sponsor too.