I can't disagree with the fact that is the first part of your statement there. That's how we train. However-
Although most Aikido training is based on reactive (go no sen) situations, there is a whole class of techniques based on sen no sen (siezing the initiative).
"O Sensei: In Aikido, there is absolutely no attack. To attack means that the spirit has already lost.
That is why I brought in the word intent. Aggressivity will only get you into trouble as would any other strong emotion such as fear.
I suggest that the apparent contradiction between sen no sen and the above quote was one of mistranslation. Replace attack with aggression and it all makes sense. Do you know the source of the translation it wasn't John Stevens was it?.