[peisistratos]

Struggle sessions aren't analogous, as they were held against class enemies (out-group). More akin are the self-criticism sessions that Maoist cadre held. Communist cadre criticized themselves. Which, if you want another analogy stretching backward, would be confession in the Roman Catholic church.

Tangentially, struggle sessions only arose to prominence during the Cultural Revolution. The main criticism of class enemies were the Speak Bitterness sessions of the 1940s, where communist cadre would facilitate a village's peasants criticism of its landlords. Despite the notion that communist cadre were instigating violence, most of Mao's letters were to cadre who were taken aback by peasant's (sometimes fatal) violence toward long hated landlords, Japanese collaborators etc.