Malbim: (a) Hashem's commands are unlike human commands, that if one transgresses them, the commander] wants to punish and take vengeance him, and kill him. Hashem wants to fix His creations and sustain them! Also when they sin and He decrees punishment on them, the purpose is not to punish and take vengeance. Rather, via the punishment he will put to his heart to repent and fix his deeds in the future. Also if He decrees death on a Rasha, the purpose is not his death, rather, so another Rasha will see, and put to his heart to repent amidst fear of punishment. "Im Echpotz b'Mos ha'Rasha" ? that is not the intent. Hashem wants to the Rasha to live! (b) You say that you became Tamei, and will melt in your deeds ? "repent from your evils ways!" Via Teshuvah you will return to your initial state, be sanctified and heal from your illness. Why should you do? You have a cure!