It seems pretty sexist to me, why were early feminists like Emmeline Pankhurst supportive of this movement? Even in 1914 when it was considered acceptable. I understand that she also campaigned for the right to work so are these connected?
For background: In 1914, Admiral Penrose Fitzgerald concocted a plan to encourage enlistment (as conscription was not introduced until 1917) - having women hand out white feathers to men who were not in uniform, implying or outright stating that they were cowards. The women he officially recruited into this were known as the Order of the White Feather.
As today, feminism has ever been more of a term for loosely allied groups with a common cause rather than a cohesive single movement. During WWI, some women's rights activists were pro-war while others were against it: Emmeline and Christabel Pankhurst are examples of the former, but Sylvia Pankhurst (another daughter of Emmeline) was a pacifist. It's often stated that early feminists as a group were pro-white feathers, but this is a misconception pushed by people with an agenda, generally, and it doesn't help that some early post-war writers blamed women for sending the men to war and that the female pacifists were strongly opposed by the press and by soldiers. The (British) National Union of Women’s Suffrage Societies expelled its pacifist members in 1915 and the (British) Women’s Social and Political Union enthusiastically pushed the war, both focusing on presenting women as full citizens who supported the government unhampered by the stereotypical qualities of sentiment and weakness assigned to them and showing that women could contribute to the public sphere as well as the domestic one. Meanwhile, the Women’s International League of Peace and Freedom united activists from all countries, taking the position that women should stand together for their rights across borders and that women being fully integrated into public life would end war. Helen Hamilton's The Jingo-Woman shows the viewpoint of a woman opposed to the white feather movement.
What has to be remembered is that popular culture strongly encouraged women to do their bit, which, before the depletion of the male workforce, was centered around pushing men to enlist. Women's duty was represented as being to give up the men in their lives: only an unpatriotic woman would prevent her willing husband/father/brother/son from enlisting out of sentiment. The propaganda of war was aimed as much at them as at men.
Edit: if you're going to downvote me, the least you could do is write OP a better answer.