Stop loss is a killer if

Stop loss is a real balancing act. Set it too close to your entry and you will get stopped out all the time but set it too far and you could get massive losses when the market turns

Stop loss really might be a killer of your profits. If you don't understand what is risk/reward ratio and you don't know how to calculate it correctly, then perhaps you should be acquianted with these things before you start trading. These things are the basic in risk management practices and if you don't want to comply with them, then you might face unpleasant consequences of such ignorance on the market. However, there are some traders who can trade without using stop loss and they have profits. Anyway, it reuires lots of experience and knowledge in order to understand how much you can afford yourself to lose.

Not really! It depends on how users used it. Stop Loss is a killer if you are unable to control your emotions like what I experienced when I am new to this.

Sometimes you cant deny for the loss, this is normal for traders face losing trades, maybe some traders say if the stop-loss is killer, but actually depending on your trading strategy, stop loss is one way to manage the risk if often hit stop loss hence you need to improve trading strategy maybe you need a better way to determine entry point and exit point.

Stop loss can be a killer if not used properly, but it also can be a lifesaver. Make sure to know when is the right time to use them and follow the rules. If a trader trades without a stop loss and the market turns against you, then you might get into serious trouble and run up a lot of losses. A stop loss order will automatically close your position for you, giving you peace of mind.