The difference is in who is being protected. In Sweden, the consumers of the nation, ie, the citizenry, is protected by allowing butter to be freely imported.
In Norway, laws have long favored domestic dairy production at the direct expense of the citizens of that country. Imports of dairy are taxed so greatly that foreign producers avoid the market altogether.
Could you ask for a clearer example of a free market and free trade vs government sponsored corporatism and the effect this has on the population?