Notice how the hoaxes, once revealed, are put in the dustbin of history? However, the message that they were meant to illustrate lives on and is repeated over and over again for decades afterwards.
The left knows that a lie can get half way around the world before the truth can put its pants on. They lie as a tactic because they value power over truth.
When you live amorally, you cannot admit that there is such a thing as absolute truth, because that takes you down a path that logically ends with right and wrong instead of shades of grey.