That is correct, tempting someone to sin is sin itself but the problem lies in the nature of the creation. Nothing that was created will be able to purify the creation. This world is all shifting mists and fog and comparisons of morality are only on the surface because the point of view is one of corruption, always. Some have been blessed with a point of view less degraded by thier innate corruption than others, and others unfortunately are destined to be completely consumed by thier innate corruption.
With that being said, it is still noble to try and help my brother avoid sinning but if GOD gave him the free will to decide if he will hurt himself or not, who am i to deny him this GOD given freedom? Am I wiser than his Creator? NO WAY.