Because of the countries designating regulation based on cryptocurrency and there are countries that have banned cryptocurrency. There are also news releases. One is that facebook has been already banned such ads about cryptocurrency, also follow the steps banned the ads about crypto are twitter and google. Many people are alarming in the news that it caused doubt or fear especially to investors, so it is also one of the possible reasons why the price of bitcoin has dropped.
There cannot be a single factor to decrease the worth of the bitcoin and the money involved in the bitcoin but many many multiple factors combine with each other and start making the things worse in the market and when all of the external factors get away, the most dangerous internal factor starts that is the panic Selling and it really make the things very much crucial and poorer for the holders, traders and the new comers.