Are pacifists optimists or pessimists?

I was at a peace conference at the weekend.  A full-time peace worker said “Of course, you have to be an optimist to believe peace is possible“.  Puzzled, I disagreed, saying “In my experience, peace activists are pessimists and do what they do because they fear the worst will happen“.  Some discussion followed.

I have since worked out the difference: he was talking about employees and I was talking about volunteers.  He could not do his job if he was pessimistic and I would have no motivation if I was optimistic.

What you can do with that knowledge, I have no idea.

But what does it mean about me going from a peace-worker volunteer to becoming a peace sector employee?