Most investors don't have the emotional toughness to appreciate dips especially when they invested at a relatively higher price and so they rely heavily on price action to choose a suitable point to invest
Because they are not actual investors.
It is more accurate to call them as speculators, not investors. Investors are people who actually do many things, due diligent research to understand about risk and potential of an asset they want to invest in, and further than that they also make their plan for investment.
Investors by understand about risk, will include it into their investment plan and also think of what they will react when price drops. They surely have their cut loss plan and even do research about the market psychology cycle.