Selling bitcoin is not a stupid decision, if they sell when the price is higher than the time of purchase, it's not a stupid decision, because it can be a strategy to make a profit, and when the price goes down they will buy back. Holding in the long run can be a good option, but to get better profits, then you should be able to choose the right time to enter the market. The crypto market is very unstable and you should be more sensitive in your choices.