The article states clearly that it wasn't just one group:

But feminist organizations protested against female conscription, among others the Norwegian Association for Women’s Rights (Norsk Kvinnesaksforening, NKF, the Norwegian Section of the International Alliance of Women, IAW) and the Norwegian Section of Women’s International League for Peace and Freedom, WILPF.

One such gender role is the stereotype that men are more brutal and less nurturing than women which leads to male-only conscription

The reason for male-only conscription is that men are better soldiers, and young women can't be sacrificed otherwise the population will collapse in the span of one generation. It's a logistical issue, gender roles have nothing to do with it.

One such gender role is the stereotype that men are more brutal and less nurturing than women

Feminism actually tries very hard to reinforce this stereotype, by constantly portraying men as the abusers and women as the victims in cases of domestic violence, and by working to devalue the role of fathers in children's life.