It's obvious not to sell in market like this but hold till ATH, that's what investors do but some can't patiently wait so they sell and it's a good time for investors who hold their investment cause we are just approaching the bull market and it's likely those patient ones will gain profit.
I don't think experienced investors sold their bitcoin cause the ones who understood how the market looks like they will not make a mistake selling their investment but we hear a lot of stories about investment plan sometimes it doesn't come with patient but with financial problem so they choose to sell, in all those who hold will be happy to sell in the bull market