Why on Earth would a group of one of the most rabidly anti-war feminists announce this 3 days after a major terror attack and less than 48 hours after France, FRANCE declared war on the Islamic State. You can’t make this stuff up.
For most of our history, actors and "entertainers" were generally ignored because their opinions were not only ill formed and unsuited to the majority of normal people, but because also because they couldn't spread them very far.
With the advent of movies and television, these silly people who "play" for a living gained both wealth and power, and what used to pass for silliness now had the means to reach the larger masses and warp their opinions too.
Those girls may know something about making music, but it is apparent that they know nothing about how the real, brutal world functions.
As you may or may not know, the so-called "anti-war" movement is led by communist organizations. Namely, Communist Party USA ("peace" group = United for Peace and Justice), Workers World Party/Party for Socialism and Liberation ("peace" group = ANSWER), and the Revolutionary Communist Party ("peace" group = World Can't Wait).
These groups support mass murderers like Mao-tse Tung, Stalin and Che. So they are not pacifist, but rather just anti-US military. They've never met a bloody leftist uprising or revolution they didn't welcome and support.