Selling Bitcoin would always be a stupid decision, because the price could be always higher. But there are people who just don't want to invest anymore and they are retiring, for an example, people who bought Bitcoins for $1 each don't need to wait anymore, they are already rich and they can retire.
I agree, selling bitcoin is the worst thing to do, Holding it in this market crises will be the best decision for everyone, having patience is needed in crypto, it is not necessary to sell your bitcoin at the lowest price, that will gain you nothing.