The main thing is panic. They see the market dumping they sell their assets without seeing their losses. They got panic. The other thing that you have mentioned which is People like Elon musk do shilling of their favorite coins and people but that coins without thinking. I hope now Elon Musk will not manipulate crypto market.
most of the problems new people invest are ambitious and greedy, who are jealous of seeing people playing crypto looking for big money easily, just want big profits but don't know the method to do. my advice for new people don't use big money for investment and use cold money...