The theism of the Bhagavatam ontologically grounds morality, while naturalism suggests moral relativism. Naturalists often posit the notion that morality is not woven into the fabric of existence, it is not an objective, intrinsic requirement of the nature of things. However, if we reject the idea that moral acts are normative truths, we must do the same with thoughts and reason. We cannot have meaningful thoughts and meaningless actions that carry those thoughts out. The reasons for denying objective moral values applies equally to cognitive values (the way we ought to think). But to deny objective cognitive values renders rationality meaningless.
The Bhagavata‘s view is that morality and ethical values are not a matter of personal opinion but intrinsic principles of the cosmos—dharma—built into the heart of reality, even as the ongoing determination of particular moral standards is arrived at with the help of reasoning in consideration of consequences.
There are moral principles and then their are time and and circumstance application of those principles. Thus Sri Krsna says in Mahabharata:
“It is difficult to grasp the highest understanding [of morality]. One ascertains it by reasoning. Now there are many people who simply claim ‘morality is scripture.’ Though I don’t oppose that view, scriptures do not give rules for every case.”