Why did Iroquois women have all of the power?

Haudenosaunee women are considered equal to men and as such the Clanmother role is equal to Hoyane (Titled Chief).

The clanmother's duties include electing the Title Chiefs and calling a council. While the Clanmothers let the Hoyane run the councils they are not allowed to make a decision without consultation with the Title Chiefs' clan and Clanmother support. All decisions have to reach consensus for a resolution to be pasted.