Think of it like this:

You are a parent with 2 children. There is one piece of cake left. How do you cut the piece so both children will be happy? You cannot cut it in half because either child (or both) will say the other received more cake.

The only good solution is to allow one child to cut the cake and the other to choose the piece they want. That way if the cake is cut unfairly, the other child get the larger piece.

tl;dr the cake is a lie