While on one hand Mari Selvaraj directed Karnan is being hailed for its realistic portrayal of historic caste suppression in Southern Tamil Nadu, on the other hand the politics of the movie is being criticized for its accuracy. To the unversed, the plot of Karnan predominantly revolves around the Kodiyankulam rampage that took place on August 31, 1995. 

During that time Jayalalithaa was the Chief Minister and the incident of police excess in the Dalit dominant section of the village left a scar in both the history of Tamil Nadu and her political regime. It was also during this time that Jayalalithaa had started naming state owned transport corporation buses after prominent personalities of regional importance. e.g. The Villupuram transport corporation were named after Thanthai Periyar, the Tirunelveli buses after the 18th-century regional ruler Kattabomman. 

When Karunanidhi took over as the CM next term, he continued this tradition and named the Virudunagar buses after Veeran Sundaralingam, Kattabomman's Chief general. Despite being a historic figure, Veeran Sundaralingam's naming was objected to due to his caste and Karnunanidhi instead of heeding to the objections scrapped off all names from the transport corporations and commonly renamed them as the Tamil Nadu State Transport Corporation (TNSTC). This was in 1997/98.

Karnan depicts both these incidents in the same timeline, leading to the debate that one CM is being blamed for the other's faults. However the movie seems to merely portray all types of caste-based suppression people faced in that Southern region, which was once the center point of continuous communal clashes and riots.