My sense of how sex/gender based oppression works is not limited to women because sex/gender based oppression extends far beyond women alone. And that's also bound up on one side of a false binary which serves to limit one's vision of what sex/gender based oppression fully entails.
So, "sisterhood" is an empty concept to me for that reason too.
It's a box too small to hold the entire populace of people whose asses are kicked by patriarchy.