When you are deceived by satan and do the work of satan, you are one of satan's minions, of course you believe you are right. Doing evil while believing it is good, does not make it acceptable in the eyes of God. The beautiful part of God's grace is that we can repent and be saved through the sacrifice of Christ. But will they do that or consider it a done deal, because they thought their evil was good? There is no salvation without repentance, no matter how good you believed your wicked deeds were. Sin is a rejection of God, and true forgiveness is a gift from God, not humanity.