I don't think trading is the same as gambling.
In trading, it is we who will determine the profit or loss. if you want to get out of a trade you made at a loss of course you do it on your own. it's not a matter of luck or a guess.
In gambling, when you place a bet, you have no control over your bet. It is the results published by the bookie that will determine your fate whether you will win or lose.
I guess the two are completely different.
It's already given above that they have some similarities but not completely the same. In trading, I thought you are the one who determines your outcome? So why say trade at a loss? It's possible to incur a loss in trading because we don't have a full control with it but it was the market.
You only compare trading with sports betting but what about casino games? When you are betting multiple times and you use the autobet function, it is always possible to stop it before you lose all your balance. In sports betting, there is also multi bets and there is an option to cash out early but the profits that you will be getting is much lesser.