I believe the issue is no longer about compliance with regulatory laws or KYC, but rather for most countries it has become a matter of national security threat because these markets pose a risk due to the leakage of sensitive information or even the influence on the country's policy.
I think you are overestimating the importance of Polymarket and prediction bets. Violations of national security and the leaking of data, intentional and unintentional happened even before prediction markets became a thing so this is nothing new. If it really bothered the countries, they can just regulate them to forbid these kind of bets and the problem is solved. Prediction markets are not going anywhere because people are addicted to news these days, so it it a product that is very easy to sell.
Personally, I like to use prediction markets because they're more decentralized, but they can really be taken advantage of by those in power. It's not the best thing to participate in, but I'm aiming to be more decentralized.
It's hard to predict, and it's prone to manipulation, so I would stick to platforms built on predictions and just bet on plays that aren't easily manipulated.
I'm just looking at the platform.
I said it before in this thread, that some people are able to win has no impact on you as the player as long as you are not making your bets based off of the odds on the market. But if you are doing that then you are betting the wrong way and doing it quite in a lazy way, so the issue would still be the player and not that someone has insider information. The insider information thing is more an issue when it comes to leaking or using information that should not be public as the user gave an example, matters of national security.