They are promoting meme coin because they want instant money, they know that meme coin is very well known this year and if they promote meme coins specially when they have a big name with big community following them in social media including telegram then they can earn.
besides that most of them become victims of their liquidity when the dumping begins after their small pumping as if the price will go up even higher. there are quite a lot of incidents if we want to pay attention to how market players sometimes only think about profit without caring about the coins they hold after that will live or die.