In other words, one man's loss is another man's gain.
It's immoral based on the same principles St. Thomas applies to usury, where you make profit without providing any value. And when people make money trading stocks it always comes at the expensive of someone else who's lost money.
No, although that's the norm, that's not always certain, for example:
You buy a stock at $10 from a guy who bought it at $9. He made $1.
You sell to a guy who shorts it at $11, you made $1.
You buy it back from him at $10, he made $1.
This can go on and on where you each take turns making profit = no one loses. I know it sounds crazy but it happens.
There actually are what they call "zero sum" instruments like futures, where there is a buyer for every seller and vise versa, but that's not how it works with stocks....or stock options.
One who does not know what they're doing should learn all about it before doing anything, or do not day trade, or probably even invest. But the main reason I say this is because the company themselves, along with the big banks and institutions make most of their money in the markets by lying to investors, which amounts to stealing their money through their bs news and bs upgrades/downgrades, manipulation, algorithmic trading, dark pools and other crooked games they play masterfully - with the help of the media of course.
Just gotta remember it's the stock market, not Sunday school. For them it's all about them and their money, we're talking about, huge, mind boggling sums of money, the bigger the crook, the more they make - at the expense of the unknowing. They're not satisfied until they get every last penny of your money if you let them, and they are very successful at it.
It's most definitely a rigged game, has been for decades at least, no question about that.