True. Unfortunately loss aversion is a fundamental part of our psychology. That's why people who are willing to take risks are rewarded. Everything from starting a business to gambling to trading involves risk. Being emotional when getting into these is a surefire way to lose money. Fear of losing money will make you lose money.
This is an outright oversimplification of matters
As if no fear of losing money would somehow prevent you from losing money. While it doesn't prevent you from losses at all, it could in fact heavily exaggerate them. Really, if you don't have any such fear altogether, what would stop you from losing all? Your fear is essentially caused by the lack of genuine knowledge, and it is the true knowledge of real situation that prevents you from losses. Lack of fear is just an effect that such knowledge gives, while unfounded fearlessness (e.g. due to arrogance or overconfidence, what I generally call "know it better" approach) can be fatal in trading and pretty fast at that
I'm talking about those who sell out of fear when they see price fall in hopes of at least getting some of their money back. IMHO you shouldn't be risking money you can't afford to lose in the first place
Stop-orders are used exactly for that
It is basically the same fear out of which traders are placing these orders. If they didn't have this fear (i.e. they were sure that the price wouldn't go any lower), they wouldn't be placing them. This is the lesser of two evils, losing small or losing big. In this way, if you just happen not to feel any fear at all (for whatever reason) and remain emotionless (no matter what), that will eventually lead you to greater losses
