I definitely understand this frame of mind. On the face of it, it seems quite absurd that anyone can do anything, e.g. insider trade, or use sock puppet accounts to manipulate information. In practice, we've seen it work okay so far!

One key realization is that individual market creators on Manifold are given the same powers that existing prediction market platform or casino bookies are trusted with today. A trader is always placing some amount of trust in the bookie to not manipulate the own market, or pricing that risk into the transaction. We hope to make this risk clear and up-front, and to reward market creators who repeatedly adjudicate markets in a fair way.