Memecoins are shitcoins except very few, there is a group of people who started investing in memecoins to get attention of new traders and after fews days of launching they sell their coins and the price drops and new people get loss. By their loss the group of investors get profit and sell their coins!
Because many meme coins are created only so that the team gets a profit. And they want to get this profit quickly, not after a few years. Having all the coins in their wallets, it is very easy to make a pump, and then sell the coins to those who believe that it is very easy to make money on such coins.