Trading can devolve into gambling, and sure there are likely more conservative trading methods that might not really be gambling, so there are not exactly bright lines in regards to the various categories, of investing versus trading versus gambling but they might sort of be on a spectrum in which many of us might not agree upon the thresholds upon which one of the practices might fall into being the next one.
You have a point, though you did not explain it well. Trading and Gambling are often mistaken because of the risks involved in the two and the way traders/gamblers find themselves in a situation to choose an option that can either make them win or lose. Most people forget that the modality of the two risky activities is different. If you are trading, you are actually doing Business, this is because you are buying and selling, and everything anyone could apply to regular business (caution, patience, management etc) can also be applied to online trading. The only difference is that you are conducting the online trading electronically and the market is so sensitive, dynamic and volatile. If you buy when you were supposed to sell/wait, you will lose. this is not different from buying and selling physical goods in the market.
However, one can still directly gamble in trading if they do not know it but just forcing things. You can imagine the person who was not sure of what the market would do, instead of waiting for a clearer signal took a position. Such a person is actually gambling. The same goes for those who did not analyse the market but still opened a trade. This could be funny to you but some people do it. To crown it all with another gambling in trading, the main aspect of trading that is similar to betting/gambling is called Options trading. Anything outside these two examples when the trader is acting professionally is Trading which has every distinction from Gambling.