Consider this:

1) someone with a gun puts that gun against your head and tells you to pay them half of your income.
2) ten strong guys put you in a cage and tell you they will let you out if you give them half of your income.
3) ten strong guys put you in a cage, and tell you they will let you out if you buy for half of your income, beany babies.
4) ten strong guys put you in a cage, and tell you they will let you out if you pay them half of your income, and then they will make sure that no other guys will put you in a cage again.
5) the gouvernment will put you in a cage unless you pay them half of your income, and in return they will make sure that nobody else will put you in a cage.  On top of that, you get a museum of modern art for it which you can then visit by paying an entrance ticket.

Where's the difference ?