This is the theoretical claim.

Now look at Polymarket's advertising. It is 100% presented as a gambling platform, not an information discovery system. There is nothing saying "don't play if you don't have insider information." I do not think that we can reasonably fall back on this defense of these platforms anymore.

I also don't much societal value in these platform's ability to suggest political events a few hours before they happen.

And this wasn't even really the original theoretical claim for these markets. The goal was to financially incentivize research and deep investigation, not to financially incentivize people who have access to hidden information by default. If somebody developed a system for predicting cease fires and used that to win in these markets then we've created a new thing for society. If somebody is just in the room when a cease fire is decided we haven't progressed society at all. All we've done is create a new way for people with power to extract personal wealth.