It's true that gambling is very different from trading, gambling is more about reducing or wasting money, you need luck in gambling to win. In trading you need skills, strat, understand well etc. The only thing they have in common is High risky. Being greedy is in people and it will never go away.
Some gambling games also need skills, too. And people also could earn money from gambling although it relies on the luck. However, the chance to win in gambling isn't as big as in trading, mostly the win chance 50/50. Meanwhile in trading, we can increase the chance to take profits if we have good skills and use proper strategies. So, that's the reason why we must have a learning process in trading. It is very recommended to focus on having good knowledge first as a newbie.
Regarding the risks, both gambling and trading have high risks. But in trading, we can deal with the risks if we have good knowledge. Meanwhile in gambling, the risks remain the same even if we have knowledge and experienced enough. Moreover for luck based games such like Slots, there is no way to avoid the level of risks. The chance to lose money will be always 50/50.