Aryans do not deviate from the instructions of Krsna, nor do they have doubts about Krsna, but non-Aryans and other demoniac people fail to follow the instructions of Bhagavad-gita and Srimad-Bhagavatam. This is because they have been trained in sense gratification at the cost of all other living entities. Nunam pramattah kurute vikarma: (SB 5.5.4) their only business is to indulge in all kinds of forbidden activities for sense gratification. Yad indriya-pritaya aprnoti: they deviate in this way because they want to gratify their senses. They have no other occupation or ambition.

Srila Prabhupada, SB 6.16.43, Purport