So I don't think any of us are effective individually. I think if it's anything it's the overall existence of a place like EvC where the collective argument is the most effective.
Which is true. We rarely get the consistent posters to change their minds (on either side). But there is a vast, shadowy network of people called "lurkers" who receive all the benefit of the discussion without any of the cost of participation.
I would guess some of the less agressive posters do more on that shadowy cabal than any of the agressive types. Though the agressive types are by far the more entertaining.