Now, I don't gamble, but in December 2020 I was able to use that platform to "bet" that Donald Trump had lost the US presidential election he lost the previous month. I "won" a bunch of money. Because lunatics had decided facts aren't true, we can just make up whatever we want, and it took a few weeks for that to get knocked down and meanwhile you could just bet against these morons.

As to financial instruments: For a bunch of the instruments you are actually buying something, and these are clearly just fine. If you buy Oil futures or Pork futures that actually literally deliver oil (or pork) and you're holding them when they come due, you're getting oil (or pork). This is probably not what you wanted, but that's what those instruments do, the people who were supposed to be buying them want oil, or pork, and so they're happy, too bad for you.

I agree that some derivative instruments might just be gambling, these instruments are also too risky and poorly understood, so if you say we should ban those with gambling I don't see why not. Again, gambling is legal in my country, and so are these derivatives, but the Americans can choose different, as they have on many things.