Because not all sins are equal in seriousness.
Are you here to tell us that stealing a nickel stick of gum is as serious a sin as cheating on your wife?
To the majority of us, probably, stealing a nickel stick of gum is not as serious as cheating on ones wife. But in Gods eyes, 'missing the mark' is missing the mark. Period. It's not a matter of missing the mark by a little bit vs missing the mark by a whole bunch. If we miss the mark (sin) and our sin isn't covered by the Blood of the Atonement when we stand in judgement...then we're in a heap of trouble.
