Coinflip is strictly on luck, how lucky we are in playing this game will determine if the luck works on our side or not by winining or loosing, we should understand games by their categories, some are not only determined by luck alone, but how skillful we appear in playing them, when we divert to trading, this is another thing entirely different from flipping coin or gambling, this is a way of making business or an investment and we choose the kind of position to take that best fit us.
That's the thing, the result or the outcome of a coin flip is determined by your luck while in trading, you need to have knowledge and experience about the market, know how to do research and analysis, you should have a general idea about where the price of a certain cryptocurrency will move next so that you can place your trade based on that. I agree that the trades a trader makes wouldn't always be correct and there can be bad trades as well since the market is unpredictable, but if you are knowledgeable and experienced, you can get more winning trades than losing ones.
So, I don't really see any reason why people would compare trading with gambling. There are some types of trading that may have some resemblance with gambling such as futures trading and options trading, but even they can be profitable for experienced and knowledgeable traders unlike gambling which will eventually make you lose.