Think about it. If morality is subjective and there is no objective standard of right and wrong, nothing prevents someone from murdering your friend and stealing his money. The murderer could not even be prosecuted, because for him murder is good. Children could be tortured, women could be raped, entire families could be locked into a blazing building to burn to death, and we could do nothing, because the perpetrators of these deeds could hide behind ‘Well, for me it’s the right thing’. Textbook sophistry, I am afraid, and not a very original nor persuasive argument philosophically speaking.