It's simple. People who are in a work place with a union should contribute to the negotiations for contracts that includes raises and changes of benefits. That is why it's called the "fair share" provision. When you give people the choice to opt out the union begins to fail because people want to keep their money. Of course when the union fails people will wonder why corporations take advantage of individuals. Remember that unions are democracy in action. Messy but you get to add your voice.