The activity of investors towards cryptocurrency is just like a chain reaction, some of the people will still hold their coins because the market price is decreasing but for those who cannot take the pressure then they will just sell their coins at its lowest price which will leads for the prices in the market to dump.
This is not just the tendency of investors towards cryptocurrencies. It is the attitude of investors to most asset classes. The term "herd mentality" existed long before cryptocurrencies came in.
You just have to think about all the investors piling in close to the peak of an equity rally....
Panic selling is not a good strategy for the investors or to those people who have not enough funds in their wallets, Hold strategy is good for some instance like if the coin or token has potential it should be keep, if not then it should be sold.