An interesting point here, how are your techniques? I can safely say that all of mine are non-violent, I thought that was what Aikido was about.
If you raise your hand to a person to cause them to fall down, if you do something to use "their force against them".....
you have committed an act of violence. Any wavering or excuse is just kidding yourself. It is an act of violence...in degrees.
The only real option for a passive person, is to stand and let them hit you-even kill you- and take any thing of yours that they wish. That takes tremendous bravery and an indomitable conviction of will. That's why true passiveness is beyond the capabilities of most people.
Interestingly, the term passive/ agressive as a mental state or attitude, can be tied into the type of lack of resolve exhibited in dealing wih people in a forthright and clear manner that is played out on Mats everywhere...in all kinds of arts. This includes MMA gyms where guys will get people in locks and crank AFTER they have tapped someone out and AFTER everyone agreed it was a casual roll. People carry their damage everywhere they go.
If you are practicing aikido you are committing violence. Get over it. Otherwise take off the martial outfit (from a culture not your own) and put down the wooden weapons...you don't belong. If you put on the funny outfit (hey, I wear them too) and pick up a weapon, be resolved at what you are doing.
I would agree with Kevin; you avoid and reduce, you prepare and de-escalate, and when you can, give a measured response. Sometimes the best response is total domination to stop the violence- with violence- to restore the peace.
Overall, I think it is important to have these issues thoroughly resolved in your own mind so that you are mentally prepared. Nothing is as calming or as definitive as being the one person in the room who is aware, prepared, and ready to act in an instant. I would offer that many times it is palpable (not always) to others.