Spies and infiltration have always and will always be a problem for leftist groups. Every revolution has to deal with counter-revolution by the ruling class. The tactics of counter revolution merely keep pace with the general state of technology, but until they start doing neural implants or something I don’t think it is that much more severe today compared with, for example, 100 years ago the Freikorps’ work during the 1918 German revolution. The USSR and Maoist China had constantly to defend themselves against internal and external counter-revolutionary tendencies. This of course is criticized by liberals as authoritarian “purges” because, to the liberal mind, all ideology is sacred as such, and above criticism. Look up as well the FBI snitches in the Black Panther Party and the surveillance of MLK.

All that has changed is today people communicate through digital media, so those media are of course insecure. The general character of revolutionary discipline has not (IMO) changed that much. If digital surveillance has only made people more aware of the reality of surveillance, then that’s a silver lining I guess.