That is only half the story. Western Union has it set up so that when your local grocery store or Post Office handles Western Union remitances, they don't need a Money Service Business license. The local outlet simply acts as a franchise following Western Union procedures/fees. That way, they can use Western Union's Money Service Business License instead.
As far as I can tell, Bitcoin will have a hard time following MSB requirements unless the regulations are chanaged. For example, you are required to send customer details along with the electronic transaction. Only certain bank wires are exempt. Bitcoin would need its own exemption. Even if you expend resources to embed this information in the block-chain, you would be running afoul with privacy legislation.