IMO gambling is gambling as long as it's purely depending on luck and no support for it on other aspects "knowing methods of trading, best methods and ways to earn, specific market analysis", if the trader doesn't know these then it's merely gambling.
No trading and gambling have a very huge difference because on one side where you are betting on your luck and in investment you are actually investing your money WITHOUT ANY RISK for small profits.
you are naive to think that investing money is "without" risk, even for small profits. any kind of investment has some form of risk involved in it otherwise there would have been no profit in it.
even the most secure investment options have some kind of risks in them. and if the business you are investing in says their business is free of risk, they are lying to you or they are ponzi.