The people selling off their Cryptos aggressively are those that don't know what crypto is all about. Those selling crypto are the ones that don't know that crypto is here to stay.Those selling off their crypto are that have not make out time to research on past  historic data of crypto.
In other words,some joined crypto in Dec 2017 just because of the bullish market crypto is into,and seeing that crypto price went down,they sell.Some expected that there will be a bullish market in the Dec 2018,but that never happened so they sell.As it stands,some don't even research on crypto they invested in.Some don't know that crypto needs time to be developed.So,once impatient people  see their predictions are not met,they start selling.
However, some have not known that the people that made huge amount of money in crypto didn't make it by selling aggressively. Some of them hold crypto for 4 years or more.They don't care if the market is moving up and down.These are verified facts some may not know,but that is the truth.