IMHO, Aikido can be seen as a nonviolent activist position to pacifism if by pacifism one means simply the position of opposing war and violence or a refusal to engage in a military activity because of one's beliefs or principles.
The philosophy is pacifists, but the application is activist. Aikido does not simply stand there and take an attack or simply comply with an attack. The attack doesn't win. Aikido teaches to overcome ones self and in so doing over comes others by how we handle their attack. But, thier attack must be handled and neutralized for them to also realize the error of their way.
Too often pacifism is the position of victims who are afraid to stand up and fight. There is a time to remember the Budo roots and that Aikido is still a martial art and actually initiate and engage those attacking as we often do in Randori.
Enough of the soapbox for this old veteran.