Why do people think that libertarians are fiscal conservatives, but social liberals?

Libertarians on the federal level want to leave these decisions to the states and local governments. This is a common sense approach the making more people happy. The fed can't create legislation that everyone agrees with because their decisions affect over 300 millions people. Local governments may only have to please 100 people. If those people share the same views, legislation could be crafted to please such a small group. If social matters were to be left to state and local governments, you would see people of similar beliefs start to group together thus getting what they want. Not only would they get what they want, they wouldn't be infringing on the beliefs of everyone else. In a perfect world, federal and state governments would be libertarian. This would leave all of the social decisions up to the town, city, or county politicians. It is much easier to vote out a city counsel person than it is to vote out a Governor, Senator, or even President and replace them with someone that you actually like.