The term alt-left originated in response to the rise of the alt-right in 2016. It’s basically a mirror term used to define a group of social media-oriented extremists. These extremists have a real-world presence as well and have staged numerous demonstrations and sometimes violent protests.
The main alt-left extremist groups are Antifa, Black Bloc, Socialist Rifle Association, and various local communist groups, which vary from city to city. The pro-abortion group Jane’s Revenge is also sometimes included.
Some of the main features of alt-left extremism are revolutionary marxist ideology, liberation theology, extremist environmentalism, anti-racism, and an idealistic worldview that their mass revolution will solve all the problems of their country.
The main targets of alt-left extremists are the police, Immigration and Customs Enforcement (ICE), various alt-right groups like the Proud Boys, and anyone they deem to be a “Reactionary” or “fascist.” Their targets constantly shift depending on current events and have lately included conservative supreme court justices who helped overturn Roe v. Wade.