"Because I want to" is a perfectly valid reason for changing your name after marriage. It is the absence of choice that is unfair to women.
Implying that women who choose to take their husbands' names are uneducated, unintelligent or lacking in self-respect is in itself sexist, because it simultaneously paints all women with the same brush while devaluing their individual choices.
You cannot empower women by acknowledging that we have a right to choose, and then condemning us when we choose "wrongly." This is oppression, not liberation.
HTH,
Michelle
P.S. I didn't change my name.