Sorry Kim but I don't understand your logic.
Women are oppressed because we are the biological group which bears children.
Men are not dominant because they are biologically superior - they are dominant because social constructions have been developed to dominate women in order to control our fertility.
The male supremacy exists as an institutionalised reality that exerts power over women in all social areas (private relations, politics, economics, etc). The existence of FTM trans does nothing to change or question this global reality.
Men, as the dominant group are not challenged in their dominance by FTM trans. At all.
The notion that women, as a biological group, do not exist, is a challenge because it effaces our right to claim and fight against our biologically based oppression.
Totally different.