By that logic market makers in the stock market are basically like a casino too. No one is of course guaranteed to win in anything but at least the stock market doesn't ban you for making too much money like a casino does.
I think we're running into the limitations of the English language. Things don't always neatly fit into categories. The stock market can be a casino, depending on how you interact with it.
If you regularly trade and constantly watch your stocks, then it's a casino.
If you buy some index funds and never look at them again until 10 years later, it's not a casino.
There's no clear delineation between an investment and a bet; it's a Venn diagram with a huge overlap. I don't think that means that there is any question about where on the Venn diagram sites like Kalshi and Polymarket belong.
There is an entire profession of Poker players that consistently make money in casinos but not from casinos. You simply don't understand how this all works.