There is a famous dialogue in the film nayagan(1987) by a boatman-cum-bootlegger "Naalu perukku nalladhu seidal edhuvumay thaappu illai" literal meaning is even a sinful act,if there are beneficiaries to it, will not be treated as sin.
Apply this dialogue in everyday's life. The people of this generation (only a miniscule portion of the society) indulge in all immoral activities like "swinging" "one-stand stands" "swapping". In conclusion, we cite that it was for the welfare of the family members. To accentuate our stand, we even quote "the end justifies the means" . As human beings, we want the logical support for our deeds.No matter how bad our activities are. No sophistry please!