That is definitely true and I think it stands for any investment. Since I am from a country which has a poor economy and isn't stable, it's always a thought to pull out/sell my investments to help me out with the situation. Fortunately, I am patient and I've never dipped because of some emergency and I never actually had to. But some people just can't meet ends with their salary so they sell even if they wanted to hold for a profit.
It would be ideal if everyone could invest and hold, but you can't really bet against the economic situation you are in.