What are the risks involved with the newspaper versus the risks involved with Polymarket?
Answer this and I think you'll discover that "no different" is actually quite different.
Regarding the stock market: nobody sane uses the stock market as an indicator for the future. People predict the stock market, not the other way around.
> What are the risks
I don't have the slightest idea what point you're trying to make with this. Journalists make lots of people unhappy with their reporting, if you're referring to risks to journalists? Indeed that's part of the job of being a truth teller.
> nobody sane uses the stock market as an indicator for the future
I don't think you understand. If you think you can do a better job of predicting the future than the stock market, you will become extremely wealthy. So how exactly do you think it isn't basically the best publicly available indicator of the future, specifically the net present value of future expected profits?
Sophisticated analysts absolutely use current stock prices/market value for modeling the future.