> As someone generally against gambling, I think there's a fair point to be made that Polymarket and similar sites are not fundamentally different from e.g. sports betting.

They are, because the object of the bet is open, it can be abused to generate incentives for desired behavior. For example if you really want the guy writing about the attack out of the picture, you don't send death threats, you instead make a new bet that says so and so does not write for X publication after Y date. Place a large bet against it and let greed and stochastic violence do the rest.