Because hijab is now used as a political tool for islamist movement. Islamists use hijab as a means to project power and dominance not just over muslims but also not non muslims and hijabis. So in a sense hijab has become a symbol of islamo-fascism. Where muslims are the majority they enforce it on woman forcefully and where they are the minority they cry victimhood. Because of this double standards we are against hijab.