What is a Shitcoin?
(sorry for the language, but there's no way around it)
"Shitcoin" is a slang term coming from "Alt Coins" which means "alternative from Bitcoin" since Bitcoin is the original and most accepted. As the US dollar price of Bitcoin rose, people saw an opportunity to make "fast money". They "invented" alternative blockchains with dubious claims of functionality. What was not disclosed was early investors (often venture capitalists) would receive free or cheap coins in exchange for investments. The invested money would be used for YouTube marketing and paying influencers. Prices would skyrocket, early investors take their payout, and retail investors are left with nothing. This scheme is often called "Pump and Dump" and has been repeated over and over.
With this backdrop, many Bitcoiners dislike or even resent the propagators of these criminal activities, these frauds. Not only for the outright deception but for making the whole environment seem risky or fraudulent. They ride the coattails of Bitcoin and shit on it.
For all these reasons, many Bitcoiners call Alt Coins "shitcoins."