There is actually only one religious principle: dharmam tu saksad bhagavat-pranitam [SB 6.3.19]. The only religious principle is to follow the orders of the Supreme Personality of Godhead. Unfortunately, especially in this age of Kali, everyone is an atheist, people do not even believe in God, what to speak of following His words. The words nija-veda-patha can also mean ones own set of religious principles. Formerly there was only one veda-patha, or set of religious principles. Now there are many. It doesnt matter which set of religious principles one follows: the only injunction is that he must follow them strictly. An atheist, or nastika, is one who does not believe in the Vedas. However, even if one takes up a different system of religion, according to this verse he must follow the religious principles he has accepted. Whether one is a Hindu, or a Mohammedan or a Christian, he should follow his own religious principles. However, if one concocts his own religious path within his mind, or if one follows no religious principles at all, he is punished in the hell known as Asi-patravana. In other words, a human being must follow some religious principles. If he does not follow any religious principles, he is no better than an animal. As Kali-yuga advances, people are becoming godless and taking up so-called secularism. They do not know the punishment awaiting them in Asi-patravana, as described in this verse.