Why do people lose money in crypto? the number one reason is panic, they tend to be controlled by emotion, for newbies never ever just bought something you really know nothing about, that's one of the rule, research is needed, your money is important so don't waste it with wrong decisions, if you decided to what coin to buy, don't sell with small movement crypto is volatile, make some target for losses and earning.
What they really feel is that they think this coin will not go up again so they sell it to reduce the risk of loss, as well as meme coins maybe the movement is small for us to buy with a large amount of money that we get.