I think there's a lot of extra interest in stocks and crypto and stocks right now, in no small part due to the likes of GME and BTC and the associated media coverage. The greater idiot theory genuinely applies here, as long as people keep believing they haven't 'missed the boat' and keep buying the market will continue to grow (bullish) and as others have said here there tends to be a cascading effect when people start to sell which reverses this (bearish).
Interestingly enough (and the reason I logged into ycombinator today) there seems to have been some attempt by unidentified parties to artificially create a bearish movement for GME, I was surprised no one has created a thread about the fact that Yahoo finance (Wallace Witkowski) had published the stock has 'plummeted' at 11:55 AM EST march 10th when the actual price drop didn't occur until 12:20 PM EST. There's definitely some dangerous house-of-cards going on in the US stock exchange. I don't envy those living there if this all falls down the way people are anticipating it will.