No sin is trivially small because every sin is a personal offense against a holy God — the error is in using 'not all sin is the same' as a license to minimize some sins.

Just because adultery is worse than a white lie does not mean a white lie is acceptable or inconsequential. Every sin, however minor by comparison, is still a sin against the God of the universe. The correct conclusion is: all sin is terrible, and within that shared terribleness, some sins are much worse than others. Mike uses the analogy of heart attacks — not all heart attacks are the same, but they are all a very big deal.