Everyone will agree with you, people that have more wealth obviously will do like you, but not with people that have lees wealth. They will always be haunted by their needed and to fill it they have to sell it.
Btw investor are clever i think like this they've to withdraw the initial capital that they've invested, profit that they got then they'll invest until whenever they want. ($100 for a month then you already got the prof $200, take back your initial capital $100) this will make you more relax and not over think it if the price will fall down significant.
Or take the profit in the time that he decided (a year, 2 years, etc.)