Well, there are some forms of gaming that aren't pure chance even though they are based heavily on that e.g. Texas Holdem Poker--there are people who make their living on playing, so they are clearly not "gambling" in the usual sense of the word.
Yes, there are forms which are similar but that does not make gambling equal to trading.
The trading volumes leave little to chance. The millions of luckless players trying to get rich fill the pockets of Blackrock. And there is an exception to that rule too. Just remember Gamestop.
https://www.cnbc.com/2021/01/27/gamestop-mania-explained-how-the-reddit-retail-trading-crowd-ran-over-wall-street-pros.htmlAs a side note its most unfortunate that to become a Retail investor has high hurdles, form a LLC with the capability to open a bank account in the US, plus funding it.