We have some of the most intelligent people in the world working on extracting as much wealth as possible from high volume trading. For someone to gain money in the market someone most lose. Imagine if we had these minds working on solving real world problems that would actually benefit society. Just like gambling, trading is zero sum.
Not everyone loses. I think what youre trying to say is that for you to make profit you will have to take the risk. When taking the risk youre not sure yet whether youre going to win or lose, youre just taking the risk because you know that there is a reward if you should pass.
There are people who are so good in trading that they hardly experience loss while trading, and there are those who are still novice and lose money every time.