Alex and Richard,
I'd advise you both to go chat with your sensei and see if he/she can make either of you see sense.
That's all on that subject from me.
As to Aikido being purely defensive, I couldn't disagree more. The philosophy may be compassionate but that doesn't mean that we cut off an entire range of technique.
Nick pointed out just one way in which tori can initiate the sequence and then there's the point that if Aikidoka aren't capable of decent attacks then the training in the dojo will suffer.
If you don't like the terms "offensive" or "aggressive" then perhaps "active" Aikido would work better.
Like that yin and yang symbol we see around all these Aikido websites.
Remove one half and it doesn't make sense.
In all the talk of peace and love people often seem to miss out the idea that O'Sensei was certainly not lacking in martial spirit and his art reflects that.
Sometimes if feels as though we're a group of people trying to learn "the noble art" (boxing) and complaining that punching people isn't very "noble."
Just my opinion.
Edit: Got called away whilst posting and didn't see Daren and Gregory's posts before posting.