There have been dozens and dozens of people's wars or revolutionary insurections and movements and so a people's war and "leftist" revolutionary movements can be shit or turn to shit without being CIA. Shining path's shitty leadership and glorifying of revolutionary violence led them to increasingly bad decisions and actions that they doubled down on culminating to losing support of peasants and rural communities. Making up shit because it would be cool no movement would ever commit those mistakes during the revolution only serves to brush off the mistakes made as "cia plants lol" and "no ACTUAL leftist movement or evolution did bad or horrible things EVER"