As far as I remember, Forex in the CIS is a synonym for the word Fraud. These are small firms that did not release their users' transactions to the market and could change quotes at any time. They did not withdraw money to those who won a lot, but immediately closed the account. I myself was registered in this, and saw this fraud. Nevertheless, if Forex is understood as an honest company, then it is the same money intermediary as a casino. I believe that there is not much difference between them, except that in a physical casino the payment of winnings is guaranteed.
I’ve never dealt with Forex, but I’ve heard several stories about brokers who earned a commission from each transaction and carried out a large number of trades just to quickly get their cutlosing the client’s money in the process, of course. So yes, most people tend to associate Forex with scams. At least personally, I’ve never heard anything good about it. I also tried registering there, even did a bit of demo trading, but didn’t go any further because I discovered the crypto market and fully immersed myself in it.