What is unethical?

The good point of prediction markets is that they provide information. This information is available to everyone, for free, which benefits everyone.

Insiders help achieve this. Insiders have information and by participating in the market they then expose and share that information. So this is good. If we ban insiders, we're just banning accurate information from getting into the market. If we do that, we might as well just ban prediction markets altogether. I don't have a strong opinion either way on that, but a prediction market without insiders is pointless.

Insider trading is unethical, and has long been recognized as such. It is outrageous for you to suggest that it is a good thing.

It is not a free market if there is insider trading. If insiders are trading other market participants are by definition getting screwed by what was advertised as a fair, impartial system.

You certainly wouldn't participate in a market where you did not think you had fair odds. Tho maybe you're inclined towards the rigging side of things.

Finally, since you're trying to work the information angle, would you care to share any legitimately meaninful information you've gained from prediction markets?