PURPORT

Maharaj Yudhisthir thinks that he was not actually in the administration of the kingdom. It was being carried by Duryodhana well without any harm to the citizens. But without being in administration he caused killing of so many living beings only for his personal gain of the kingdom from the hands of Duryodhana. The killing was committed not in the course of administration but for the sake of self aggrandisement and as such he is thinking of being responsible for all the sins.